What Do Sloths Eat? Sloth Diet, Food, and Digestion

What Do Sloths Eat? Sloth Diet, Food, and Digestion

  • Sloths are folivores
  • It takes up to 30 days to digest a leaf
  • Ambient temperature affects sloths’ digestion
  • Sloths eat small quantities of leaves per day
  • Sloths have unusual toilet habits

What is a folivore?

A folivore is an animal that specializes in eating leaves. From the Latin folium meaning “leaf” (same root word as foliage) and the suffix -vore, meaning “to eat” or “to devour”, it refers to any animal that exclusively or primarily eats leaves.



All species of sloths are folivores. The three-fingered sloth eats leaves and occasionally seed pods (like Cacao pods), while the two-fingered sloth has a more varied diet that sometimes includes both seed pods and fruit.


sloths chocolate
Three-fingered sloth (Bradypus variegatus) eating a cacao pod.

What kinds of trees do sloths eat?

Sloths as a species eat leaves from over 90 different kinds of trees, however, any given individual usually rotates between half a dozen to a dozen kinds of trees. They inherit these preferences from their mothers.

Sloths are iconically associated with the Cecropia, and indeed these trees are an important part of reforestation programs that help restore sloth habitat. However, sloths need much more diversity in their habitats and diet than this. Montgomery and Sunquist (1975) listed 28 tree species and three lianas used for food by nine Brown-throated sloths (B. variegatus) and Queiroz (1995) listed 16 plant species in a study also carried out with Brown-throated sloths in the Mamirauá Reserve, in the Amazon.

Three-fingered sloths:

  • Cacao pods and leaves (Theobroma cacao)
  • Sangrillo (Pterocarpus officinalis)
  • Cecropia spp.
  • Colorado (Luehea seemannii)
  • Chilamate (Ficus insipida)
  • Sapotaceans (Micropholis venulosa)
  • Fig trees (Ficus spp)
  • Apocynaceas (Mandevilla sp.)
  • Moraceae
  • Euphorbiaceae
  • Bombacaceae

Two-fingered sloths:

  • Bobacaceae flowers
  • Barrigon leaves and  flowers (Pseudobombax septenatum)
  • Liana
  • Espave (Anacardium excelsum)
  • Poró (Cochlospermum vitifolium).
  • Jobo (Spondias spp.)


How do folivores digest food?

Trees evolved leaves to collect and process sunlight, not to be eaten, and leaves have very tough cell walls containing large amounts of cellulose. Mature leaves may also contain chemicals that build up over time and make the leaves toxic if eaten in large quantities. Leaves also contain very few calories compared to other food sources, and in order to eat enough leaves to meet their energy requirements, folivores have some unique feeding habits and specialized digestion.



To avoid toxins and tough cellulose, sloths favor fresh new leaves that typically grow on the end of branches. They move from tree to tree, eating fresh leaves from a variety of sources. This means that any toxins present in one type of leaf are unlikely to build up over time in the sloths’ bodies.


Baby two-fingered sloth


Sloths do not digest the nutrients from leaves directly. Instead, they have a very complex digestive system that enables bacteria in the sloths’ gut to ferment and break down the leaves; the sloths derive their caloric and nutrient requirements from this gut bacteria.

How does ambient temperature affect sloths’ digestion?

As with most mammals, the gut bacteria of sloths are sensitive to temperature, however, sloths are poikilotherms, meaning that compared to most mammals sloths do not maintain a constant body temperature. Instead, the ambient temperature of the surrounding rainforest determines how warm or cold a sloth is. This is a very efficient evolutionary strategy to help sloths save energy and camouflage them from predators that detect infrared radiation (such as some snakes), but it makes sloths very vulnerable to extreme temperatures.


sloth basking
Sloths also bask under the sun / Photo by Cristhian Chentiko


If a sloth gets too cold, the bacteria in their gut can die and leave the sloth unable to digest any more food. Even if the sloth warms back up, the bacteria will have been killed off and the sloth could starve to death—even with a full stomach full of leaves. In rescue centers that specialize in rehabilitating wild sloths, emergency probiotics taken from healthy sloths can replenish this gut bacteria and save a cold sloth from starvation.

How much do sloths eat?

Sloths do not eat a large quantity of food on a daily basis. The average dry weight of leaves eaten by any given three-fingered sloth is approximately 73.5 grams (2.5 ounces) per day. This is only one-third of the amount eaten by howler monkeys, which eat many of the same leaves, live in the same habitat, and are about the same size as sloths. Sloths eat slightly more on warmer days, but there is little variation in food intake between individuals, suggesting that sloths’ feeding habits are very well optimized for their environmental conditions.


baby sloth eating fruit leaves


Sloths drink water

A long-held presumption in ecology is that sloths get all the water they need from the foliage they consume, and few documented observations exist of either of the two sloth genera  (Bradypus and Choloepus) drinking in the wild.


sloth drinking water
Male Three-fingered sloths drinking water / Photo: Suzi Eszterhas

Rainforests, in general, are becoming hotter and dryer with global warming. In addition, fragmented forests in urban areas tend to have hotter temperatures in the understory, because of more light penetrating the forest. Dr. Rebecca Cliffe believes that this is making urban sloths need to drink more and travel further to find water.

How do sloth moms feed their babies?

Sloths are mammals, which means that they nurse their young on milk. Baby sloths crawl onto their mother’s stomach immediately after birth and cling to her, suckling small amounts of milk throughout the day. Producing milk is energetically expensive, so sloth moms can’t store much milk–instead, they produce milk on-demand as the baby needs it.


sloth mother feeding her baby leaves
Baby sloths learn from their mother what leaves are good to eat / Photo: Suzi Eszterhas

What do baby sloths eat?

Young sloths begin supplementing their diet with leaves as young as one week old. Baby sloths are very curious about what their mother is eating, and they will sample leaves from her mouth as she eats.



As they do this, they learn which leaves are good to eat and which to avoid, and this early exposure will stay with them throughout their lives. Teaching baby sloths which leaves to eat is a major challenge for rescue centers that seek to raise orphan sloths to return to the wild.

What do captive sloths eat?

Many captive sloths live in zoos far from their native tropical rainforests. This can make getting fresh, natural foliage for sloths’ diets very difficult, and so many organizations will feed sloths whatever plants are available, such as vegetables, including root vegetables and plants from non-tropical climates, which they have not evolved to eat.



The typical food plate for a two-fingered sloth in captivity consists of boiled carrots, eggs, flowers, celery, green beans, and bananas. This diet has far too much glucose for sloths and can lead to health complications including diabetes and heart disease.

It is theorized that this has a negative impact on sloths’ health and lifespans, however, this will only be confirmed once scientists can better evaluate the lifespans of wild sloths and compare them to sloths living in captivity.

How long does it take sloths to digest leaves?

Sloths digest leaves like they do everything else: slowly. A single leaf can take up to 30 days to pass through the sloth’s digestive tract. Unsurprisingly, this is the slowest digestion rate of any mammal. Humans, for example, digest their food in 24 to 72 hours (1 to 3 days) depending on what kind of food it is, and hummingbirds can complete a digestive cycle in 10 minutes.


baby sloth eating leaves


Sloths’ digestive systems

Sloths have some very unusual anatomy, and their digestive system is no exception. Of particular note is the fact that a sloth’s esophagus has a loop in it; instead of connecting in a direct line from the mouth to the stomach (as in humans), it forms a loop like a roller coaster. This helps any swallowed food stay in the stomach while the sloth hangs upside down in the trees.



Their unusual esophagus keeps sloths’ food in their large, four-chambered stomachs no matter what. A sloth cannot vomit, belch or even fart, so it is very important that they do not eat anything bad for them or anything that produces excess gas.


Image from the paper: Sloths (Bradypus variegatus) as a polygastric mammal (Ellen Y. E. Mesquita,Paola C. Soares,Luise R. Mello,Elisa C. B. Freire,Ana R. Lima,Elane G. Giese,Érika Branco)


Some amount of gas is produced from the gut bacteria as part of the digestion process; this gas is diffused into their bloodstream and carried away to be slowly expelled through the lungs or skin. Sloths’ large stomachs also act as a floatation device when the sloths must swim across rivers to reach new territory.


Image: Catriona Gibb


Are sloths geophages?

Geophagy is when animals intentionally eat earth or soil, including clay, chalk, or termite mounds. Two-fingered sloths have sometimes been known to eat dirt from the ground, which is a far cry from their usual diet of leaves from the sky! Animals may do this to aid in digestion, absorb toxins, or access nutrients not found in their usual diet. It is thought that the sloths engage in geophagy to supplement nutrients and minerals that are sometimes not available in leaves. 


How are sloth toilet habits unusual?

Sloths are very particular about how and when they go to the bathroom. Although they live in the canopy, they travel all the way to the forest floor to poop. Wild sloths defecate approximately once per week, and they can poop out as much as 30% of their body weight when they do.



Sloths’ pooping ritual involves climbing down to the base of a tree, doing a special “poop dance” that includes wiggling their rear end back and forth, and in the case of three-fingered sloths, digging a small hole with their tail to poop in. Two-fingered sloths do not have tails and skip this step. When they are finished, the sloth climbs back up the tree and resumes hanging out in the canopy. Sloth feces is rich with nutrients and makes an excellent fertilizer for the trees they inhabit.


Do sloths eat the algae that grows on them?

Sloth fur is a miniature, mobile ecosystem that the sloths carry around with them. Fed by rainwater, algae grows on the hair, moths reproduce in sloth feces and then migrate back to a sloth to begin the life cycle over again. It was once speculated that these verdant green algae acted as a kind of garden, fertilized by moths, that the sloths would eat (from themselves and each other), supplementing their diet with nitrogen and phosphorous.


Photo: Suzi Eszterhas

While sloths groom their fur daily, they do not lick their fur like a cat would, and they are not social animals and do not engage in social grooming. The algae grow in specialized cracks in the sloths’ fur and are not found in sloths’ digestive systems, suggesting that they do not consume it. Additionally, there is no evidence suggesting that the algae feed off of moths or their byproducts.

The role of sloth moths and how they benefit the sloths is not well understood, and much more research is necessary to understand the details and unique nature of the sloth fur ecosystem.

-Rebecca Cliffe

Forests, the sloths’ home

Forests, the sloths’ home

Forests are areas of land covered with trees. “Forest” is a very broad term that encompasses many different types of ecosystems, varying degrees of tree density, tree type, and land management. The first fern-like trees appeared on Earth about 380 million years ago, and today forests are the dominant land-based ecosystem on the planet, with 45% of all forests on Earth being found in the tropics.

Forests come in three distinct categories


Temperate forests occur in temperate climes; areas with distinct spring, summer, autumn, and winter seasons, and low humidity levels. Most of these forests are found in North America and Europe.

Boreal forests, also called evergreen forests, are largely made of coniferous evergreen trees. They are characterized by extremely cold temperatures, and most such forests are found in North and East Europe, and Northern North America.

Tropical forests grow in tropical climates; they are widespread throughout places such as Southeast Asia, Western and Central Africa, Central and South America, the Island of New Guinea, and Australia. Tropical forests cover approximately 12% of the Earth’s surface.

Tropical forests, where sloths live

Tropical forests, often called jungles, are biodiversity hot spots. They produce almost 22 gigatons of biomass per year—talk about the opposite of a carbon footprint!


View of green lush rainforest in costa rica Free Photo
Rainforest in Costa Rica / Photo: Freepik

Tropical forest temperatures usually range between 21°C (70°F) and 30°C (86°F), with humidity ranges between 77% and 88%. Unsurprisingly, rain is frequent in tropical forests, reaching up to 1000cm (almost 33 feet) per year–however, due to the humidity and temperature, tropical forests produce their own rain, and up to 75% of water cycles within the forest, evaporating from and raining back down on the same ecosystem.

In spite of the comparatively small area they occupy, tropical forests hold 50% of the world’s biodiversity–and no one yet knows exactly how many species live there.

In addition to rainforests, tropical forests also include high elevation cloud forests, so called because of the near-constant presence of fog and mist.


Reserva Biológica Bosque Nubloso Monteverde - Go Visit Costa Rica
Cloud Forest in Monteverde, Costa Rica. /Photo: Govisitcostarica.com

This is due to lower temperatures that cause water to evaporate slower. As a result, cloud forests are very humid. Cloud forests exhibit much greater differences in elevation and topography than rainforests. The peaks and valleys contribute to the formation of “clouds”. Rainforests are warmer and found at lower elevations.

Rainforest Structure

Rainforests are split into four vertical layers, each possesses different features depending on the level of rain, light, and air circulation. The layers are mutually dependent on each other and work together to form a rainforest.

rainforest structure
Source: Global Forest Watch


Emergent Layer

The emergent layer is the highest layer of the canopy, reaching up to 60m (200ft) tall, consisting mainly of thin branches and fewer epiphytes (plants that grow on other plants) than the lower layers. Sunlight in the emergent layer is consistent and abundant, however, the strong winds strip moisture from exposed leaves, so trees usually have a waxy top layer on these leaves to prevent wind chapping.


Emergent layer. Photo: Wikipedia/ Ben Sutherland

At this level, pollination occurs by the wind. The animals found at the emergent layer will be small and light, able to navigate spindly branches or flying creatures such as birds, including one of the main sloths’ predators, the Harpy Eagles.

Canopy Layer

Found beneath the emergent layer, the most densely populated section of the rainforest is the canopy layer–this is where most animals live, along with a large variety of epiphytes. The high density of leaves and branches in the 6m (20ft) thick canopy blocks a lot of the rain, wind, and sunlight from reaching the layers below.


canopy jungle
Canopy bridge at Monteverde, Costa Rica. Photo: Patricio Novoa

As with the emergent layer, leaves in the canopy have developed a waxy surface to retain moisture, and have evolved a pointed shape that prevents water from collecting on them.

Most fruit in the rainforest is found in the canopy layer. Many plants use this method for seed dispersal, as the fruit attracts a wide variety of different species of birds, mammals, reptiles, and invertebrates.

Understory Layer

The understory lies beneath the canopy and above the forest floor. It is a dim area with little direct sunlight and very little wind. The understory is home to most of the flowers found in the rainforest. These flowers are big, brightly colored, and aromatic in order to stand out to pollinators in the low light of this layer.

Protected from the wind, the leaves found here are usually large, and it’s common to find many fenestrated (provided with openings or apertures) species, such as Monstera.



This layer is shielded from strong winds and the most intense rain by the canopy layer above, but still has adequate sunlight to make a perfect habitat for amphibians to maintain their moisture and thermo-regulation.

Forest Floor Layer

The darkest and lowest layer of the rainforest of the forest floor. Very little sunlight and less wind reach the forest floor, while rain trickles down after being filtered through the layers above. This makes it difficult for plants to grow there. Tree saplings struggle to grow tall enough to punch through the upper layers and into the sunlight.

Atlantic Forest, Brazil. Photo: The Sloth Conservation Foundation

The forest floor is where the building blocks of the rainforest originate. Leaves, branches, fruit, seeds, animal waste, and anything that starts out in the high layers of the rainforest eventually fall to the ground. Many small invertebrates assist in this decomposition and are preyed upon by larger animals and foragers. The forest floor is also home to tropical river ecosystems, which may be wide enough to allow sunlight to penetrate or may be narrow and shallow, and dark.

As debris falls from the trees and decomposes into the ground, nutrients vital for life are released into the soil, are taken up by the roots of trees, and eventually dispersed throughout the many layers of the rainforest.


Forests of Costa Rica

Costa Rica is mostly covered in tropical forests; it claims the title for largest biodiversity to landmass ratio, holding 6 – 10% of the world’s biodiversity, yet only 0.03% of the world’s landmass.

In 2020, it was reported that over 50% of Costa Rica was rainforest, but less than 25% of which was primary rainforest. 28% of Costa Rica is protected forest in the form of national parks.


costa rica forests
Change in forest cover in Costa Rica between 1940 – 2005. Costa Rica is now the only tropical country in the world that has managed to actually stop and reverse deforestation

Why forests are important to biodiversity, climate, and humans (and sloths)

More than three-quarters of Earth’s plant biomass is found in forests. This acts as an important regulator of climate, temperature and water cycle. Plants sequester carbon and produce breathable oxygen; a single full-grown tree produces an average of about 100 kilograms (220 lb) of oxygen per year.


Tropical forest distributions and carbon stored by biome (in gigatonnes). Tropical and subtropical forests store more C than any other biome (Riccardo Pravettoni, UNEP/GRID-Arendal, http:// www. grida. no/ graphicslib/ detail/ carbon-stored-by-biome_ 9082))


Forests are also critical regulators of the watershed, acting as both water purifiers and flood control. They help stabilize soil, fix nitrogen, and prevent erosion.

Forests and humans

Humans have a long and sometimes complex relationship to forests. On one hand, they are necessary to the healthy functioning of Earth’s biosphere and provide many important resources, such as timber, fuelwood, and medicinal plants; on the other hand, the space taken by forests is often desired to feed urban sprawl and agriculture.

Many traditional societies rely on forests to provide all essential resources and their ways of life are severely threatened by increasing deforestation.

Bribri man
A Bribri man from Talamanca region. Photo: Life, Culture & TRavel Costa Rica


Additionally, forests are home to approximately 80% of Earth’s terrestrial animals. Rainforests in particular host almost half of all living animal species, two-thirds of all flowering plants, and more than one-quarter of all-natural medicines (discovered to date). They are also the only place in the world where sloths live in the wild.

Sloths and forests

Sloths are arboreal neotropical animals, meaning that they live in the trees of Central and South America. These trees must be rainforest trees that receive over 250cm (100in) of rainfall per year, provide a wide variety of tree types and leaves and have good canopy connectivity for sloths to move among.


sloth in canopy rainforest
Two-fingered sloth sleeping in the canopy


Some sloths, such as the endangered pygmy sloth (Bradypus pygmaeus) only live in the mangrove forests of the Panamanian island Escudo de Veragua, while Hoffman’s two-fingered sloth (Choloepus hoffmanni) are more tolerant of a wide variety of forest habitats.

Ironically, the healthier a forest is, the harder it is to see the sloths! This is because an ideal rainforest habitat has tall, dense trees with a very connected canopy layer, which acts as perfect camouflage for our green, furry friends.

Deforestation threatens all of us: the planet, the people, and the sloths.

Illegal logging for hardwoods, slash and burn agriculture, and clearcutting for agricultural and urban sprawl are huge threats to tropical rainforests. Some estimates project that more than a quarter of all animal species could go extinct within the next 50 years if this level of deforestation is not halted.

There is good news though: if given half a chance, forests naturally renew themselves. Planted treelings send the message that open areas are not parking lots, canopy bridges give wildlife a safe way to continue being part of the ecosystem, and responsible ecotourism gives a financial incentive for struggling economies to invest in the future.

Sloths are an excellent umbrella species for rainforest ecosystems because when we save the sloths, we save the trees, and when we save the trees, we save the world, and when we save the world, we ultimately save ourselves.

-SloCo Team

About Sloth Parasites

About Sloth Parasites

A parasite is an organism that lives in or on a host and benefits by deriving nutrients at said host’s expense. A parasite differs from a symbiote in that a symbiote offers some benefit to the host in exchange.

There is very little research on parasitic infections in sloths. The majority of research that has been conducted has taken place on captive sloth populations, which live a very different lifestyle than wild sloths, with very different diets, vulnerabilities, and exposure.

Are sloths full of parasites?

Sloths have green, algae-colored fur that hosts a vast number of invertebrates, and one may think that so much flora and fauna would signify a relationship balanced heavily in favor of parasites.


Sloth moths are unique to sloth fur! /Photo: Suzi: Eszterhas


However, these organisms are not parasites, and they do not cause any negative effects or ill health in the sloths. Most of the organisms that call a sloth home have a mutualistic symbiotic relationship, where both the sloths and their passengers benefit.


Coccidia oocysts in a fecal flotation from a cat. The cat was underweight and had diarrhea, showing signs of coccidiosis
Coccidia oocysts in a fecal flotation from a cat. The cat was underweight and had diarrhea, showing signs of coccidiosis. Photo: Joel Mills – Own work, CC BY-SA 3.0,

Coccidia parasites are commonly found in domestic and captive wild animals, including sloths. Coccidia includes a wide variety of parasites that produce varying degrees of disease severity, from mild diarrhea and appetite suppression to dehydration.


Captive sloths have frequently been found to be infected with Eucestoda, commonly known as tapeworm. All types of tapeworms parasitize vertebrates and colonize their digestive tracts, living anywhere from a few days to multiple decades. This type of infection is characterized by diarrhea and weight loss over time.


Taenia saginata adult 5260 lores.jpg
This is an adult Taenia saginata tapeworm. Humans become infected by ingesting raw or undercooked infected meat. In the human intestine, the cysticercus develops over 2 mo. into an adult tapeworm, which can survive for years, attaching to, and residing in the small intestine. Content Providers(s): CDC.

(Giant) ticks

Thanks to their low body temperature, sloths are not as prone to tick infestations as most mammals. However, sometimes when sloths spend extended periods on the ground (such as when they are moving between deforested areas), they may pick up ticks during tick season.

sloth tick
A tick found in a three-fingered sloth (Bradypus variegatus)


Amblyomma varium is known by parasitologists as the giant sloth tick, as it is host-specific to Bradypus and Choloepus sloths. It is one of the largest tick species in the world.


Garrapata gigante hembra, adulta, ingurgitada (teleogina) de Amblyomma varium
Although the specimen of the picture is big, the biggest A. varium was found in French Guyana, weighted 7,5 g, and had 3,2 cm of length (Floch y Fauran, 1958).

Skin parasites

Captive sloths have sometimes been diagnosed with scabies, which is caused by the mite parasite Sarcoptes scabiei. This zoonotic skin affliction is characterized by itching and a bumpy rash which can be easily treated with topical anti-parasite medication. Special care must be taken when dealing with scabies, which is easily transmitted via contact with an infected person, or even fabric items an infected person has been in contact with.


A photomicrograph of an itch mite (S. scabiei). Photo: Kalumet – de.wikipedia


Secondary skin infections due to itching are common, and animals afflicted with this parasite will often lose drastic amounts of weight. Scabies in animals is often referred to as sarcoptic mange.

Flesh-eating parasites

Leishmaniasis is a zoonotic (meaning “carried by animals”) disease caused by the Leishmania parasite.

Colloquially known as “papalomoyo” in Costa Rica, Leishmaniasis is a common affliction amongst coastal Caribbean populations. Cutaneous (meaning “of or on the skin”) leishmaniasis is the most common—and luckily the most treatable—variation of the disease. However, Leishmaniasis is not isolated to the tropics; it is found on almost every continent, most commonly infecting humans and dogs, and sometimes cats and horses.


Female sandfly. Photo: CDC/ Frank Collins



The disease is usually transmitted through the bite of female sandflies, who inject the immature form of the parasite (promastigote), which then matures inside the host (you, me, our pets), produces more promastigotes (baby Leishmanias), which are then transmitted back to sandflies via another bite, and the cycle begins again.


Leishmania lifecycle



It is possible for Leishmaniasis to transmit by other routes, such as from a mother to an unborn child, or through the reuse of unsterilized needles, but the most common transmission mode is through sandflies. The presence of this disease in Europe is mainly due to the translocation of pets around the world.

So what does this have to do with sloths?

A commonly believed myth associates sloths with leishmaniasis, although this myth varies in its specifics. Some say a victim can acquire the disease by being bitten by a sloth, others claim that sandflies live in sloth fur. While sloths do have a whole ecosystem living within their fur, sandflies do not and cannot live on a sloth. Sloth bites in humans are infrequent and could not transmit Leishmaniasis.

As with most myths, there is a grain of truth at the heart of this one: sloths are reservoir hosts of the Leishmania parasite. This means that the parasite can live in them without causing disease in the sloths. In fact, studies have suggested that sloths are one of the largest Leishmaniasis reservoirs in Central and South America. Reservoir hosts, such as sloths, dogs, and cats, cannot pass the disease onto humans.

The cycle of the leishmania parasites in nature. Image: “Wild and synanthropic reservoirs of Leishmania species in the Americas”


Several different forms of Leishmaniasis exist. They vary in severity depending on if you have contracted cutaneous (of or on the skin), mucosal (of or on mucus membranes, such as inside the mouth or in the nose), or visceral (of or inside vital organs) leishmaniasis.

Cutaneous Leishmaniasis is the least severe version, causing skin lesions and swollen lymph glands, and visceral Leishmaniasis is fatal if left untreated, causing fever, anemia, and hepatosplenomegaly (enlargement of the liver and spleen).

A personal story

SloCo’s founder, Dr. Rebecca Cliffe, once contracted cutaneous leishmaniasis, which developed into mucosal leishmaniasis. “I remember the sandfly that bit me. I was walking my new puppy on the beach at dusk and was annoyed by the itchy bump that later appeared on my arm. I forgot about it and only really noticed something unusual when the bite was still there two weeks later.”

“We watched the little hole in my arm slowly grow for 4 weeks before deciding to have it tested. Within 24 hours, the doctor had called and told me that I had tested positive for leishmaniasis and should begin treatment immediately. I didn’t know it at the time, but that was just the tip of the iceberg.”

“As it turned out, there are no nice treatment options. The Costa Rican method involves up to 60 injections of glucantime – a toxic chemical that kills the parasite but also comes with a high risk of liver and heart damage. That didn’t sound like much fun, so I decided to seek treatment in the UK since I had been due to return during August anyway. When I finally arrived at my doctor’s office and presented him with a flesh-eating parasite, he looked at me like I had two heads. I was advised to go to the emergency room at the Liverpool School of Tropical Medicine to find more specialised help.”

“Depending on the species of leishmania I was infected with, I now had two treatment choices:

1) I could be admitted to the hospital for three weeks of intravenous medication (chemotherapy), which basically involves the same toxic chemicals as the Costa Rican injections (think heart problems and liver failure). Famously, TV presenter Ben Fogle endured this treatment after contracting leishmaniasis in Peru, and he ended up bed-bound with pneumonia – no thank you!

2) OR I could trial a new oral medication from Germany called Miltefosine. This horrifically expensive drug comes with a bunch of awful side effects, including sickness so severe that many people simply can not finish the treatment. This option wasn’t guaranteed to work either and had never before been used to treat leishmaniasis from Costa Rica. Furthermore, this medication is only effective against one subspecies of the parasite – the most dangerous subspecies.”

“As it turned out, fate made the decision for me. I was diagnosed as having the dangerous subspecies (one that is prone to infecting the mouth and nose causing disfigurement) and so I was prescribed 4 weeks’ worth of Miltefosine pills.”

** You can read about Dr. Cliffe’s experience here: http://beckycliffe.com/battle-leishmaniasis-flesh-eating-parasite/ **

-SloCo Team

Sloth Mating: Not as slow as you think

Sloth Mating: Not as slow as you think

Sloths are mysterious animals—people usually only see them sleeping or resting on their trees. It is rare for anyone to witness sloths in the act of mating, and thus there is little information about sloth reproduction.

What there is to know on the topic, however, can be found in the Slothopedia!

How does one tell a male sloth from a female sloth?

Three-fingered sloths

Male and female three-fingered sloths can be easily distinguished once they’ve reached sexual maturity, as males have a distinctive orange and black stripe on their backs called a speculum. The speculum fur is shorter and downier and covered with a slick oil that gives the fur in that area rich yellow and orange colors.


A male three-fingered sloth (Bradypus variegatus) with a research backpack / Photo: Suzi Eszterhas

Females have a much more subtle stripe on their backs, and may not have any stripe at all. They typically have a dark line surrounded by lighter fur in the same spot as a male would have a speculum.


sloth mating
A pygmy sloth (Bradypus pygmaeus)  with a baby. / Photo: Suzi Eszterhas


The exception to this is the endangered three-fingered maned sloth, which does not have a speculum. The sex of maned sloths cannot be determined without an exam. Both sexes have a shaggy black mane around their necks. The appearance of the mane is unique to each individual, and it is not currently obvious if there is any sexual dimorphism in regards to its appearance.


maned sloth brazil
Maned Sloth (Bradypus torquatus) at Reserva Sapiranga, Brazil with a GPS backpack

Two-fingered sloths

In two-fingered sloths, distinguishing between males and females is notoriously difficult. This has led to some embarrassing mistakes at zoos and rescue centers, where two sloths thought to be of the same sex have been put into the same enclosure, only to produce a newborn baby some months later!


two-fingered sloth genitals anus
Two-fingered sloth (Choloepus hoffmanni)


It is not possible to determine the sex of a two-fingered sloth without a very detailed physical examination, as they do not have any external secondary sex characteristics like the three-fingered sloths do.

This kind of exam is only possible under veterinary supervision and generally is also under anesthetic for the safety of the examiner. Two-fingered sloths are more aggressive and slightly faster than three-fingered sloths.


Two-fingered sloth penis and anus
Two-fingered sloth penis and anus. Female genitalia looks very similar.


Someone who is experienced in the science of sloth anatomy can clearly sex two-fingered sloths in such an examination, but many institutions lack knowledgeable personnel with the required expertise.

Mating season

Many animals mate only during certain times of the year. This mating season is related to the length of the days, temperature, latitude, and food availability, among other variables.  By only mating during a specific season, the females will give birth at an optimum time of the year to increase their offspring’s chances of survival.


deer mating
White-tail deers (Odocoileus virginianus) have a distinctive mating season that usually runs from October to December.

There are mixed reports as to whether sloths have a mating season. In areas where the climate is favorable year-round, females come into estrus monthly. However, in regions with distinct dry and wet seasons, the sloths may have their fertile periods such that the birth of their young coincides with the most favorable conditions.

Very little research has been done on the topic as it relates to sloths. Researchers suspect the mating seasons of sloths differ depending on the region—Central and South America have several microclimates which make mating seasons hard to determine.

In the South Caribbean of Costa Rica, sloths mate all year round and do not follow distinct seasons. In areas with more extreme seasonal changes, researchers have reported some breeding patterns, but these have yet to be fully investigated.

How to find a mate

A female three-fingered sloth will enter estrus once a month for approximately seven days. During this time her activity levels will increase by about 200% (that’s a lot for a sloth!) and she will emit high-pitched vocalizations to attract the attention of nearby males.



These vocalizations, or “screams”, sound like bird calls or shrill whistles. She will do this for eight to ten days every single month, with the vocalizations increasing in frequency until she is screaming every 10 to 15 minutes.

The male three-fingered sloths get very excited when they hear this call and will go in search of the female making it.


Two-fingered sloths don’t vocalize; instead, they secrete pheromones from their genital glands, which they rub all over trees and branches for potential mates to follow.

Some researchers observe that females will come down to go to the toilet every day while in heat. It is thought that this is to do with pheromone secretion and her feces will advertise her status to males in the area.


Once a female sloth is in heat she will wait for the males to come to her. All male sloths in the area will move through the canopy towards the female, and if more than one male responds, they will fight over mating rights. 


sloth fighting
Two males Bradypus variegatus fighting / Photo: Suzi Eszterhas


Often the aim of a sloth fight is to knock the opponent out of the tree. The victorious male will move forwards and take up a position in the same tree as the female.



These fights can be surprisingly vicious, and the losing male will signal defeat by “crying”—another high-pitched vocalization that sounds similar to the female estrus call.

The act

Despite two-fingered sloths having been bred successfully in zoos, sloth copulation itself is rarely witnessed and there is little known about the act. Footage has shown sloths mating in all different orientations; hanging upside down, front to back, face to face, hanging precariously from branches… sloths do it any way they like.



How long does it take?

Sex is the only thing sloths do quickly. Copulation lasts less than a minute. After it is over, the dominant male will stay nearby for several days, mating with the female frequently and fighting off any other males that wander too close.

This diligence takes its toll, however, and being a sloth, he also needs to take regular naps. When the dominant male is sleeping it opens a window of opportunity for any males that have been waiting nearby to sneak in. The female will mate with these other males while the dominant male is sleeping.


Gestation and birth

The gestation period for two-fingered sloths is 11 months, after which the female will usually give birth to one baby. Twins are very rare.


mom and baby sloth
Two-fingered sloth female (Choloepus hoffmanni) with a baby / Photo: Sloth Conservation Foundation


No one knows the gestation period for three-fingered sloths, as they have not successfully reproduced in captivity. Preliminary estimations of wild three-fingered sloths indicate the gestation period is probably much shorter than the two-fingered sloths, at around six months.

Are sloths monogamous?

Like most mammals, sloths are ´promiscuous’. The male will mate with as many females as he can find, and the females will mate with all the males who are able to approach her.

Homosexuality in sloths

Sloths of the same sex can form close bonds with each other when raised together in captivity, but there have been no reports of same-sex mating acts in the wild.


Juvenile Linnaeus two-fingered (Choloepus didactylus) sloths in captivity.

Breeding in captivity

Three-fingered sloths are very delicate creatures and do not thrive in captivity. Most three-fingered sloths are very likely to die within a few months of being captured and do not live long enough or are healthy enough, to breed.

This is a double-edged sword for the species. On the one hand, it prevents the breeding of three-fingered sloths in captivity for the purpose of exploitation or the pet trade, however, it also reduces the options for species conservation if three-fingered sloths lose their wild habitats.

Two-fingered sloths breed relatively well in captivity. However, the females do not show any visible signs of pregnancy, so without an ultrasound, it’s nearly impossible to tell when a female is expecting.


-Dr. Rebecca Cliffe

Founder and Executive Director


The Etymology of Sloths’ Names

The etymology of Sloths’ Names

Etymology is the study of words, particularly, the history of words. Thus, the etymology of a word is its origin and developmental history. So what is the etymology of the word sloth? And how does its scientific and common name share the same meaning?

An unfair name

When Europeans first encountered sloths, it is fair to say they were not impressed. Sloths are the only animal whose common name is derived from one of the seven deadly sins.

In 1749 the French Naturalist Georges-Lois Leclerc de Buffon described them thus:

“Slowness, habitual pain, and stupidity are the results of this strange and bungled conformation. These sloths are the lowest form of existence. One more defect would have made their lives impossible.”


Buffon 1707-1788.jpg
Undoubtly, Comte Buffon was a quite fancy man. Portrait by François-Hubert Drouais – Musée Buffon à Montbard


Sometimes common names are not always scientifically accurate, so let’s take a look at the history of “sloth”.

Slow and lazy across all vernacular languages

It’ll come as no surprise to anyone that the word sloth has many negative connotations. Through its etymology, this unconstructive word goes back to its earliest meanings in Old English(slǣwþ), which translates as “lazy” or “inert”.


sloth illustration buffon
The illustration of a sloth from the Comte de Buffon’s ‘Histoire Naturelle’


In most languages the name for sloth (the animal) is equivalent to some form of sloth (the attribute): slowness, lateness, indolence, or laziness–leading to centuries of stereotyping sloths as creatures lacking in competence and motivation.

The first European documented naming of our furry friends comes from the Portuguese “preguiça” which in turn comes from the Latin word “pigritia”, meaning “slow”. We can still hear echoes of this in the modern Spanish name for these animals: “perezoso”.

How do species come by their scientific names?

Carl Linnaeus is known as the father of modern taxonomy. Taxonomy is the scientific study of naming, defining, and classifying groups of biological organisms. The word finds its roots in the Greek language τάξιςtaxis (meaning ‘order’, ‘arrangement’) and νόμοςnomos (‘law’ or ‘science’). Linnaeus was the first to implement binomial nomenclature or the “two-term naming system” by which we refer to all fauna and flora today.

Carl von Linné.jpg
Carl Von Linné by Aleksandr Roslin – Nationalmuseum press photo

The first part of a scientific name identifies the genus, which is a taxonomic category that ranks above species and below family (e.g. Bradypus). It is always capitalized. The second part of a scientific name identifies the species (e.g. variegatus) and is usually descriptive and always lower case.

The rules Carl Linnaeus implemented are rigid, strict, and drummed into biologists at the very beginning of their studies. Done right, these names are very useful since they can describe several features of the species in only two words. 

In this list, you can find the Greek and Latin words most commonly used in systematic names, along with their English translation. Take a look–we bet you’ll find some interesting examples!

The name Xenarthra

Sloths and their cousins, the anteaters and armadillos, are part of an ancient Superorder called Xenarthra. Xenarthra” literally means “strange joints”. The name has its etymological roots in ancient Greek, with xénos (ξένος) meaning  “foreign” or “alien” and arthron (ἄρθρον) meaning “joint”.

armadillo and anteater


Most mammals have very similar skeletons, with the same number of bones in the same places, stretched or shrunk or shaped accordingly. Xenarthrans, however, have somewhat strange skeletons compared to other mammals, and each family member has a slightly different joint adaptation. Sloths, for example, have an anomalous number of cervical vertebrae and surprisingly numerous ribs.


Bradypus trydactylus skeleton

The superorder Xenarthra is split into two different orders – Pilosa and Cingulata. In biological classification, orders, like superorders, are capitalized.

The order Pilosa includes both anteaters and sloths, and translates to “the ones with fur”. Cingulata comes from Latin word for belt Cingula and this order includes armadillos as well as the extinct glyptodonts and pampatheres.

Sloth Genus

The genus (remember, a genus ranks below order and above species, and is the first name in the scientific binomial system) names for the two- and three-fingered sloths (the animal) are synonyms for the word sloth (the attribute).

The Greek words for “lame” and “slow” combined with the Greek word for “foot” (“pódi”) give us Choloepus and Bradypus–translating to “lame footed” and “slow footed” respectively.

Fingers (not toes)

Two sloth species–Choloepus didactylus (Linnaeus two-finger sloth) and Bradypus tridactylus (Pale-throated sloth)–take their Latin species names from their most distinctive features: their fingers.


Choloepus didactylus Bradypus tridactylus-min


Dactylus” comes from the Greek word meaning “finger” or “digit”. The three syllables of the word “dactylus” are thought to each represent a phalangeal bone in a finger: da-cty-lus.

Didactlylus translates to “two-finger” and tridactylus translates to “three-finger”–highly appropriate names for the most distinguishing feature of each sloth species.


The three-fingered sloths

Bradypus variegatus: Brown-throated three-fingered sloth

Variegatus shares its root with other words we still use today–variable, variegate, and all its variations–meaning made of different sorts and colors. Variegate is a common description and is used scientifically for many different animals and plants whose colors are mottled and changeable. One example is the brown-throated three-fingered sloths, who have pale to dark grey fur as well as distinctive speculums on their backs.


Bradypus variegatus
The different shades and colors of Bradypus variegatus

Bradypus pygmaeus: Pygmy sloths

The word “pigmei” was first coined as we know it by the ancient Greek philosophers Homer and Herodotus to describe people from northern Africa and Asia. However, the etymology of this word reaches even further back and was originally used as a unit of measurement. “Pygmē” was a “cubit” or “fist” (“pyx” in Latin, think “pixi”) which measured around 34 centimeters (13.5 inches) and was commonly represented as the distance from one’s elbow to one’s knuckle.


Pygmy three-fingered sloth Bradypus pygmaeus . Isla Escudo de Veraguas, Panama. Photo: Suzi Eszterhas

Bradypus torquatus: Pale-throated three-fingered sloth

The Latin word “torqueō” means “to twist and bend”. It gives us the word “torque” as in torque wrench, and also the word “torture”. With their nine cervical vertebrae (two more than most mammals), three-fingered sloths have the ability to turn their heads a full 270°, which probably seemed quite torturous to early biologists, and likely had some influence on the sloth’s Latin species name.


maned sloth brazil
A Maned Sloth turning its head. Photo: Suzi Eszterhas

Two-fingered sloth names

It is a very human thing to name things after ourselves, even when what we are naming is another species of animal.

Choloepus didactylus, literally “lame-foot” “two-fingered”, is the scientific name of the Linnaeus two-fingered sloth, named after the very same Carl Linnaeus mentioned above; the prominent figure of natural biology and father of taxonomy.


Linnaeus two-fingered sloth
Linnaeus two-fingered sloth


The other species of two-fingered sloth is named for Karl Hoffmann, a German naturalist who was the first person to give Choloepus hoffmanni, or Hoffmann’s two-fingered sloth, its taxonomic classification. (He also named three bird species, a snake, and a millipede after himself.)

two fingered


It is wrong to say that these men were the first to “discover” these animals, as generations of people indigenous to the areas had been observing these animals long before European biologists came along to give them their scientific names, but etymology is literally the “history” of words, a word which itself means a written record of the past. Cultures whose oral or written history was lost or destroyed lost their etymology along with their history.

Giant sloths and ground sloths

The most famous giant sloths are of the genus called Megatherium, from the ancient Greek words “mega” (big) and “therio” (beast)–a perfect name for a sloth the size of an elephant.

giant sloth


Another famous genus is called Mylodon, from Greek “mule” meaning “mill, molar” and “odous or odont” meaning “tooth”.

Megalonyx is yet another genus of giant ground sloths, this one from “mega” again and the Greek word “ὄνυξ”, which means “claw”. Megalonyx is therefore the genus of “big claw”. “ὄνυξ” also became the Latin word “onyx”, which came directly to English as the gemstone of the same name, representing the fingernail-like looks of some of the lighter stones.

Three-toed sloths? Or Three-fingered sloths?

The two species of sloths are commonly called either three-TOED or two-TOED sloths, however, this naming is not precise. Technically, all sloths have three toes on their hind feet.–the distinctive numbers of digits are on their hands, therefore, the proper name should be three-FINGERED and two-FINGERED sloths.

It’s likely that the alliteration of the words “two” and “three” with the suffix “toed” keeps this name in circulation, but if you want to sound like a scientist without having to learn Latin and Greek, you can start by telling your friends: technically, there is no such animal as a two-toed sloth.

What do sloths give to humanity?

What do sloths give to humanity?

To measure a species only by the benefit it brings to human civilization is to take a very narrow view of the magnificence of life on Earth. Every organism has an important role to play in its own ecosystem, and if we are humble enough to receive their gifts, sloths have so much to give us.

In these unprecedented times–when our very existence is vulnerable to the effects of climate change and global warming–it is imperative to understand that nature is not at our service. It is time to outgrow our anthropocentric mentality.

As we approach this season of generosity and gratitude, let’s take a moment to appreciate what the world’s slowest mammal has given to us. It’s more than you might think!

1 – Sloths could hold the cure to some human diseases

In 2014, an in-depth analysis of the algae growing on sloth hair discovered that A) sloths have an entire ecosystem in their fur, and B) it serves a much greater purpose than mere camouflage! Substances produced by the algae protect against a number of diseases, including some not well studied by science, as well as a specific kind of breast cancer.


Photo: Suzi Eszterhas


This very important piece of research has been taken out of context and exaggerated as it’s spread around the internet, so don’t believe everything you read. In the last 40 years, an estimated 50% of all new medical drugs were discovered from natural sources—it’s not surprising that we’re getting such great results from novel research in sloths!

2 – Sloths are an umbrella species, protecting all wildlife—and a lot of people

To save sloths, we must first save their ecosystem, and when we do, we help every other species that depends upon it.



It all starts with the trees. Trees are the giant substrates of the rainforest ecosystem, and these trees need to be connected to one another so that wildlife can safely move among them. Many rainforest animals are arboreal—meaning they live their lives in the treetops—and sloths, in particular, depend on a connected canopy for survival.


jungle rainforest


A healthy rainforest is one where trees are not isolated islands in a sea of urban sprawl, but a continuous world of leafy green biodiversity. When the canopy-dwelling creatures can stay in the canopy, humans benefit from fewer zoonotic diseases, improved environmental stability, improved infrastructure (because wildlife isn’t using the power lines as highways), and fewer traffic accidents.

Finally, there are many indigenous communities whose culture, customs, and identity are inextricably intertwined with the natural world. When we save sloths, we are literally saving the world, for everybody!


indigenous bribri woman costa rica
Bribri woman in Talamanca, South Caribbean / Photo: Life Culture Travel Costa Rica

3 – Sloths give us an antidote to haste and hurry

We have many sayings, stories, and fables about how “slow and steady wins the race”, but in the rat race of our modern world, these lessons are easily forgotten. Sloths have been around for millions of years, proving that you don’t have to outrun life in order to survive it!



Costa Rica’s moto is “Pura Vida”, which means “pure life”. It is a greeting, a goodbye, a synonym for “oh well, stuff happens”, and sometimes a congratulation. Sloths epitomize “Pura Vida”. As the pace and stress of the world continue to accelerate, it becomes not just pleasant, but vital to take a step back and reassess our values.


sloth sleep
Photo: Suzi Eszterhas

We must take time to appreciate the beauty that grows outside of the rat race, contemplate our decisions made in haste, and learn to prioritize mental and emotional health. If we are willing to listen to their wisdom, sloths can teach us how to calm down, relax, and take it easy. After all, sometimes “slowly” is the fastest way to get to where you want to be. Pura Vida!

4- Sloths make us laugh

There are probably more important things in the world than a cute picture of a baby sloth sticking its tongue out at us… but right now it’s a bit hard to think of what those things might be. Sloths’ popularity has skyrocketed over the last decade–for the very good reason that they are perfectly adorable—and this can only be a good thing.


young offsprings


We all need to laugh more, share more, and reflect on our own absurdity. Nothing does this better than the enigmatic smile of a sloth meme in your inbox! Really, any animal that can show us how to take ourselves a bit less seriously is doing us a very great service.


scale of sloths quarantine

5 – Sloths give us mystery

Many common, seemingly simple questions about sloths have the same answer – nobody knows. How long do they live? How long are they pregnant for? Exactly how many species are there, anyway?

Nobody knows.

Photo: Suzi Eszterhas

Even stranger are the things we do know, like that sloths are three times stronger than humans, they carry around their very own ecosystem on their backs, and they can survive falls from heights that would kill most other mammals.

The best thing about scientific discoveries are not just the answers that we discover, but the questions that those answers spawn. The more we know the more there is to wonder about; ultimately it is the endless curiosity that drives us, the wonder that enthralls us, and the mystery that gives us purpose.

6 – Sloths evolved the avocados

We here at Team Sloth are hardcore avocado fans – smashed on toast, guacamolied onto chips, sliced in a burrito, fetched by our dogs when they fall off trees in our yard… really. We’re not making that one up. Dogs, after all, like to fetch things, and the jungle would eat any newspapers foolish enough to be tossed into our yard, so the dog retrieves avocados.

Those same fruits rain down on our tin roofs like the Wrath of Armageddon at 3:30 in the morning, so it’s really only fair that we get a meal out of the deal.


For both our interrupted sleep and our tasty new-age toast, we have sloths to thank. Specifically, the ancient ground sloth, Megatherium.


Illustration of a Megatherium: Bruce Horsefall

Thousands of years ago when giant ground sloths roamed the Western Hemisphere, they were the only herbivores big enough to eat the avocados and (and their equally giant seeds). The huge seeds passed through their digestive systems and were dispersed all over the Americas, where the avocado eventually outlived the giant sloths that spawned them.

Thank you, Megatherium! Rest in peace! We’ll take good care of the guacamole, we promise.

If you’re feeling particularly grateful to sloths and want to learn more about how to keep up this mutually beneficial relationship, you can donate here.


-Ames Reeder

Urban Sloth Project Assistant


Baby Sloths: Everything you always wanted to know

Baby Sloths: everything you always wanted to know!

A baby sloth is fully reliant on it’s mother to teach it how to survive in the canopy of the rainforest. They are fragile yet fascinating little creatures, and here you can learn everything you ever wanted to know about baby sloths!



Giving Birth to a Baby Sloth

A two-fingered female sloth will give birth to a single baby after a gestation period of 11.5 months, while a three-fingered sloth is thought to give birth after approximately six months. Biologists have never had the opportunity to follow a three-fingered sloth all the way from conception to birth, and so this gestation period is still only an approximation.

When it’s time to give birth, the mother will usually descend to the lower canopy branches and give birth while hanging upside down. In this position, if the baby falls to the ground, it won’t fall far, and the mother can climb down to retrieve her young.


baby sloth birth
A three-fingered sloth after giving birth, Costa Rica / Photo: Agustín Murillo


The afterbirth usually falls to the forest floor and female sloths have been known to descend to the ground to consume it – it is very common for animals in the wild to ingest the afterbirth, even herbivores like sloths, probably for a nutritional boost or to avoid attracting the attention of predators.

Occasionally, sloths have been known to give birth to twins, but there is only enough room on the female’s chest for one baby and the sloth’s very slow metabolism only provides enough resources for one, so the weakest twin will usually be rejected.


Baby Sloth Features

A baby sloth is born ready to face the world with eyes open, sharp claws, and fully formed teeth. It will instinctively cling to it’s mother’s fur immediately after birth and crawl up towards the safety of her chest where she begins the process of cleaning the young with her mouth.


baby sloth
Three-fingered sloth (Bradypus variegatus) newborn baby (less than 1 week old) clinging to mother. /Photo: Suzi Eszterhas.


The weight and size of baby sloths differs between the six extant species.  Three-fingered sloths are smaller than two-fingered sloths. A newborn baby sloth typically weighs between 300 – 500 grams, with three-fingered babies often weighing less than two-fingered babies.


baby three toed sloth
This three-fingered sloth is a 2 day old orphaned baby/ Aviarios Sloth Sanctuary, Costa Rica / Photo: Suzi Eszterhas

How much do baby sloths sleep?

Despite the common myth that a sloth will sleep for 20 hours per day, adult sloths in the wild actually only sleep for an average of 8 to 10 hours per day.

Currently, no research has been conducted into the sleeping habits of wild baby sloths, however, if we extrapolate data from other mammals, we can hypothesize that baby sloths will sleep for a larger portion of the day than adults as they do not have to be on the constant lookout for predators or forage for food – their mom’s do that for them!

Adult and baby sloths in human facilities (zoos/rescue centers) sleep for an average of 15 hours per day.


baby two toed sloth yawning
Cute baby two-fingered sloth yawning after a hard day of… sleeping.


Raising a baby sloth

Male sloths, as with most mammals, don’t care for their young. The female sloth will spend up to 12 months of her life raising her baby alone.

The baby clings on the mother’s chest for approximately six months, regularly suckling small amounts of milk throughout the day.


baby sloth pale throated nursing
Pale-throated sloth (Bradypus tridactylus) mother and three-month-old baby / Sloth Island, Guyana / Photo: Suzi Eszterhas


Sloth mothers don’t store large amounts of milk like most other mammals – carrying a heavy supply of milk around is expensive in terms of energy. Because baby sloths are always clinging onto their mother’s chest, females save energy by slowly producing small amounts of milk throughout the day instead.

As well as drinking milk, baby sloths will begin to sample leaves from around their mother’s mouth from as early as 1 week old – this is how the baby learns which leaves are good to eat!


baby sloth eating leaves with mom GIF


Exploring with mom

While young baby sloths usually spend the majority of their time on their mother’s chest, they will occasionally cling onto the fur on her back. This usually happens while she is crawling across the ground, however, as the baby grows it will begin to move around more, and will often take this opportunity to explore what is going on around mom.

At first, this will be reaching out to grab different leaves and branches with two or three limbs, still maintaining a connection with mom, but as the baby slowly gains confidence (and becomes too heavy for mom to carry), they will spend an increasing amount of time next to mom, rather than clinging to her.


baby sloth luna sol
This is Luna and Sol (Moon and Sun) and they are part of our Urban Sloth Project.  On the ground, Sol will climb onto his mom’s back, but he is usually hidden from sight when they are up in the trees as he will curl up into Luna’s chest. Recently, we have been seeing more of Sol as he grows more adventurous.


Learning to poop

Once a week, the mother will climb down to defecate at the base of a tree. The baby sloth will start pooping following the patterns of the mother.

The ‘poop dance’ is something that all sloths do immediately before and after they defecate, and it involves wiggling around at the base of the tree. This dance helps them to clear a space in the leaf litter for them to defecate into, and then cover up the evidence of their weekly journey to the ground afterward. Three-fingered sloths are particularly good at this as they have a short stubby tail that helps to dig a deeper hole!



Falling from the trees

Sometimes a baby sloth will fall from its mother’s chest to the ground where it is very vulnerable to predators.

Sloths are built to survive falls of up to 100ft to the forest floor – however, they are not adapted to fall onto concrete or roofs. As more of their jungle home disappears, sloths are less likely to survive falls.

When a baby sloth falls and becomes separated from mom, they will cry to alert their mother to where they are. Mom will climb down from the canopy to retrieve her baby, but as sloths have a top speed of 2mph, this journey will take a lot of time and energy.


sloth ground
The ground is not a safe place for a baby sloth.

Reuniting with mom – with the help of humans!

In urban areas, well-meaning members of the public may assume that a baby sloth on the ground is in trouble, and will take them to a rescue center before mom has the chance to reach her baby. Rescue centers have developed a technique to reunite mothers with their babies in these situations, by recording the baby’s cry and playing the recording on a loudspeaker where the baby was discovered.

Baby sloth cries are loud, but the jungle is louder (especially in urban areas where cars and construction noise pollute the air). If mom is still around, she will spring into action and slowly head towards the cry coming from the loudspeaker. The lost baby can be placed on the tree trunk once mom is close enough, and mom can scoop her baby up and return to the canopy.


sloth mom mother


However, if a baby falls from mom too many times, mom may stop retrieving them. This is because a mother will perceive something wrong with a baby who cannot hold onto her fur consistently, and with survival being the name of the game in the wild, a mother who has an indication that her baby is not completely healthy is likely to reject them.



There have been reports from rescue centers that mother sloths have come down from the canopy to their babies, only to sniff them and climb back up without the baby, showing the baby sloth has been truly rejected by the mother. In this case, there is a high risk that the baby has congenital abnormalities. Not to mention, climbing up and down from the canopy repeatedly exerts a large amount of energy from a sloth who does not have much to spare!



cute baby sloth climbing learning GIF
Rescued baby sloths learning to climb.


What should you do if you find a baby sloth close to the ground? Keep watch until nightfall, unless the baby is in immediate danger from predators. If 12 hours have passed with no sign of the mother, please contact your local rescue center.

Crying Baby Sloth

Sloths are usually silent creatures as their greatest survival techniques are camouflage and stealth. However, baby sloths will call for mom when they are separated, and this creates some of the cutest sounds and noises imaginable.

Three-fingered baby sloths make a high pitch squeak, while two-fingered babies sound like baby goats (they ‘meep’).



Baby Sloth Diet

As a baby sloth grows, it learns what to eat by copying exactly what its mother is eating. At first, the baby will eat the food from around the mother’s mouth. As it gets older, it will begin to reach off of her body to grab leaves for itself while she is feeding. Through this process, the baby sloth will learn essential lessons about which tree species are safe to eat.


baby sloth feeding image picture
Three-fingered mother and newborn baby (less than 1 week old) feeding from Cecropia leaves / Photo: Suzi Eszterhas


Although sloths are known to feed from more than 90 different tree species, an individual will rotate among approximately seven to 12 favorite feeding trees – a strategy that prevents them from overeating specific toxins present in the leaves. When babies begin to eat leaves fresh from the trees, rather than mulch from their mom’s mouths which are already partially broken down due to enzymes in her saliva, mom will direct her baby to the youngest, most tender leaves of the tree.


Sloth mother
A sloth mother feeding on Cecropia leaves while her baby is watching / Photo: Suzi Esterhas


Not only do these young leaves have lower levels of any potential toxins, but the cellulose cell wall of the plant is less well established in young leaves, making them easier to digest.

Due to their incredibly slow metabolism and rate of digestion, if sloths were to feed from the same tree species for too long, it is thought that they would intoxicate themselves. Sloths learn this behavior and inherit their feeding tree preferences from their mothers, which may be why releasing hand-reared sloths into the wild can be particularly difficult.


Baby sloth eating flower GIF
Hibiscus flowers are like candies for baby sloths, and common food in rescue centers and sanctuaries.

Green Offsprings

Baby sloths will look very different from their mothers when they are born. Adult sloths tend to have some algal and fungal growth on their outer fur, whereas babies are born with only the soft, downy undercoat. They develop coarse outer fur at sexual maturity.

Wild sloths begin to develop their green color after approximately 18 months, as algae, fungi, and insects pass from mother to offspring. For this reason, sloths raised in captivity do not develop the famous green coloration, as they are not interacting with any wild sloths who do have flora and fauna growing on their fur.


young offsprings
These young sloths raised by humans haven’t yet got algae growing in their fur. 


Becoming Independent

At about six months old, the baby sloth will begin to venture off the mother’s body and spend more time hanging out close by. As independence draws closer, the distance between mother and baby slowly grows.

Eventually, the mother sloth will completely leave her original home range and move to a neighboring patch of forest. This is an unusual method of separation for a mammal, as typically the baby is expected to disperse and establish a territory elsewhere.


baby pygmy sloth
Baby pygmy three-fingered sloth (Bradypus pygmaeus) hanging on a tree close to its mother. / Photo: Suzi Eszterhas


Three-fingered sloths weigh 1 – 1.5kg once they reach independence, while two-fingered sloths weigh closer to 2kg.

After separating from its mother, the juvenile sloth becomes solitary and will only choose to interact with others when finding a mate. And now the baby sloth life cycle is completed.


Juvenile sloth and mother
A juvenile two-fingered sloth (Choloepus hoffmanni) in the same tree as its mother.


A rare case: three-fingered sloth ‘adopts’ a two-fingered sloth baby

Cross-species adoptions in the wild are exceptional events, and very rare to see. At the end of 2020, we received a highly unusual report of a three-fingered female that adopted a two-fingered baby in Costa Rica.


Three-fingered sloth 'adopts' a two-fingered!


The reasons behind this behavior are still unknown, and at the moment there are no reports of a similar case. According to the naturalists that were following them on a daily basis to gather data and information,  they looked very comfortable together. You can read more about this case here.


How to make a baby sloth

Sloths reach sexual maturity at approximately two years old. However, when you are a slow mover without much energy to spare, finding a mate can be difficult.

Female three-fingered sloths have found an unexpected solution to this problem – they scream! When she enters estrus, a female will emit high-pitched vocalizations to attract the attention of males.



Two-fingered sloths do not vocalize. Instead, both males and females mark their scent by rubbing their anal glands against tree branches to send messages about their reproductive status.

While sloths will typically only descend from the canopy to relieve themselves once a week, a female sloth will make the long journey down to the forest floor every single day when she is in estrus. Pheromones present in urine and feces are an incredibly important method of communication for all types of sloths and are likely the reason behind their unusual defecation habits.


What is the name of a baby sloth?

There are a lot of names for babies of different animal species: calf, kitten, fawn, cub, piglet, duckling, etc… but we don’t yet have a specific name for a baby sloth! Scientists, biologists, and zoologists usually use the generic words  ‘offspring’, ‘young’, and ‘baby,’ of course.

The Sloth Sanctuary of Costa Rica suggests the word ‘Slowbie’ to refer to a baby sloth.


 kissing kisses
A two-fingered sloth and a three-fingered sloths touching noses before kissing each other.

Baby sloths in captivity

Raising rescued young sloths in the nursery, a rescue center, or zoo is difficult for a variety of reasons.

No one has collected a large enough sample of sloth milk for thorough analysis, as mothers produce milk drop by drop as needed by their baby. This makes it very difficult to know what rescue centers should be feeding orphaned babies!

Most have found that a mixture of mineral water, pureed vegetables, powdered goat’s milk, and supplements can provide an alternative for orphaned sloth babies. 

Sloths are not able to digest the large fat particles found in cow’s milk, and so this can be fatal if fed to them by mistake.


baby sloth feeding eating milk
Rescued two-fingered sloth (Choloepus hoffmanni) drinking goats milk from a specialized syringe


As mentioned above, sloths eat a wide variety of leaves, and it can be a long process to find the right leaves for each sloth. The broadness of their palate is hypothesized to correlate with the trees the baby was sampling from their mom’s mouth. Choosing leaf species present in the area the sloth was found can help with picky eaters, however, rescue centers are limited by time and resources, and the selection of leaves is based on the availability of trees in the proximity of the rescue center.

In addition, baby sloths will often refuse to eat older leaves (which are the most readily available for rescue centers), and the leaves must be freshly cut. This creates a huge daily job for the facility, which takes up a lot of time and resources.

Rescue centers will release the now-rehabilitated adults in areas with an abundance of the tree species they were most fond of in captivity.


baby sloth feeding
Bottle-feeding a 2 day old orphaned newborn three-fingered baby (Bradypus variegatus) is a skilled task. / Photo: Suzi Eszterhas


Cuddly toys and blankets

Baby sloths cling onto their mother’s fur for the first part of their lives. Baby sloths have a biological need to hold onto things due to the structure of their muscles – it is this characteristic that makes sloths so well adapted for life in the trees!

In captivity, baby sloths do not have their mothers to hold on to, which is an extremely stressful experience for them. Baby sloths calm down immediately when given something to hold on to.

In fact, recording a baby sloth’s cry for the purpose of attempting to reunite them with their mother is often done by simply removing whatever the baby is clinging to. To satisfy this need, a rescue center will use stuffed toys and blankets to replace the mother.


orphan blanket
In case you need it, here’s a selection of smiling baby two-fingered sloths (Choloepus hoffmanni) wrapped in blankets


 After a quarantine period to ensure the baby is not carrying any disease which can be passed onto other sloths, a common technique is to put several orphaned babies together, where they become like magnets to each other. This not only allows the babies to hold onto another living, breathing sloth but also aids in maintaining their core body temperature.


baby sloth too cute pics
Hoffmann’s two-fingered Sloths (Choloepus hoffmanni) hugging each other for comfort / Photo Suzi Eszterhas


Baby sloth kisses!

It is also quite common to see rescued baby sloths kissing each other. While it’s tempting to anthropomorphize these baby sloth kisses as affectionate, it’s likely that this behavior is being displaced from sharing leaf-mulch from their mother’s mouths. Wild sloths will also sometimes share ‘kisses’ like this which is thought to be a way of transferring important gut bacteria and enzymes that aid in digestion.

Baby sloths are often seen suckling on other baby sloths’ ears, which is also thought to be a displacement behavior from suckling on their mothers in the wild.  However, it is likely that baby sloths will only perform this behavior if they are comfortable and experiencing very little stress.


baby sloths kissing mom kissing baby GIF
Mother cleaning and kissing her baby.


The problem with orphaned baby three-fingered sloths:

Rescue centers receiving orphaned baby three-fingered sloths are still trying to find the correct protocol to raise the species to adulthood and prepare it for release into the wild. There is currently only a handful of institutions that are able to raise orphaned three-fingered sloths successfully, and unfortunately, very few of these have been considered appropriate for release back into the wild.

Zoos featuring sloths only display two-fingered sloths, usually Linnaeus’ two-fingered sloths (Choloepus didactylus). This is because two-fingered sloths are much more successful in captivity than three-fingered sloths, with the Bradypus species having exceptionally short lifespans in captivity.


Three-fingered sloths are very fragile and hard to keep in captivity.

Do baby sloths get used to people?

Sloths do not humanize in the same way as other mammals, and it has not been reported that orphaned sloths raised in captivity become attached to their carers. Sloths do become desensitized to the presence of humans, and current reports from rescue centers that have released captive-raised sloths have shown that these sloths are attracted to the presence of people.

It is not thought that humanized sloths seek out humans for affection, but it is more to do with seeking out what is familiar. Sloths are creatures of habit, and the inappropriate protocols for raising orphaned baby sloths within some rescue centers does not properly prepare them for life in the canopy, leading to an increased amount of human-animal conflict. When platforms and human food, such as vegetables, are provided throughout the raising process, and little preparation for life in the wild is conducted, sloths will often seek out human habitations, as that is what they know to be ‘safe’.


sloth mom clinging
We like to think that the baby sloths need us and love us, but the truth is the opposite of that! /Photo Suzi Eszterhas


Sloths do not show affection towards people, and in fact, may even actively dislike people. Studies have shown that human physical contact with captive-raised sloths who are desensitized to human presence will still trigger a stress response.

It is for these reasons that rescue centers are advised to have as little physical contact with the sloths as possible, utilizing the babies’ biological need to hold onto something by transporting babies on stuffed toys to avoid any physical contact with their carers. Baby sloths will place themselves on their toys for feeding, replicating the position they would be in to suckle from their mothers.


 fight GIF cute pics
Although they need each other, baby sloths fight a lot!


Can I have a pet baby sloth? Can I buy a baby sloth?

Owning a baby sloth is wrong for a multitude of reasons. Firstly, as mentioned above, it is very hard for even professional wildlife carers to keep baby sloths alive, and raise them for release.

Sloths are not affectionate creatures by nature, and while they may form bonds with each other as babies, this will usually disappear by adulthood. Sloths become extremely stressed when experiencing human contact – their smiling faces are deceptive, they do not show many outward signs of stress. Swiping is one way that sloths exhibit stress, and even this is often misinterpreted by humans as ‘waving.’


Sloth Selfie A.K.A Slofie | Bored Panda
In this viral photo, the young sloth is showing signs of stress. The arms open means they are in defensive behavior.


Sloths can be up to three times stronger than a human being, and can cause significant injury to people if given the opportunity. Two-fingered sloths, who fair better in captivity than three-fingered sloths, also have four razor-sharp pseudo canines which will easily slice through human flesh.


sloth teeth pet
These are still just baby teeth. The bite of an adult sloth is very painful and can be dangerous.


Sloth adoptions!

However, you can still symbolically adopt a sloth for you or a loved one! You can choose physical, virtual, or VIP packages! 100% of the proceeds of these adoptions go towards funding our conservation programs to protect sloths in the wild.

Adopt a Sloth


Baby sloth hugging toy GIF


Looking for something else that is full of cute baby sloths? The Official Sloths Wall Calendar, with interesting sloths facts written by Dr. Rebecca Cliffe and adorable photos by wildlife photographer Suzi Eszterhas! Proceeds from the calendar also go directly towards helping sloths in the wild!


Sloths 2021 Wall Calendar


Searching for the Elusive Maned Sloths of Brazil

Searching for the Elusive Maned Sloths of Brazil

If you are a fan of sloths, you might think that there are two main types:

  1. Two-fingered sloths with their blonde fur and quintessential pig-like noses. There are two different species within the Choloepus genus.
  2. Three-fingered sloths with their mottled grey fur and iconic black ‘masks’ around the eyes. There are currently four different species of three-fingered sloth all grouped together within the Bradypus genus. 

But scientists are starting to realize that there is actually a third type of sloth. One that has the size, strength, and ferocity of a two-fingered sloth, but the physical appearance of a three-fingered sloth.


maned sloth brazil
Photo: Cecilia Pamich – The Sloth Conservation Foundation


It is a species that no one really knows anything about, and one that scientists think is so unique that it might belong in a completely separate genus (called Scaeopus).

These are the maned sloths of Brazil, and they are the most endangered species among the continental sloths. 

What are maned sloths? 

Maned sloths (Bradypus torquatus) are technically a species of three-fingered sloth, but they look and behave very differently to the three-fingered sloths that you might be used to.

Current research suggests that they separated off from the other sloth species approximately 19 million years ago and have been evolving independently ever since. 


maned sloth taxonomy brazil
Current Taxonomy and phylogenetics of Xenarthrans. The green circle shows the moment when maned sloths split off from the other species of three-fingered sloths / Image: Professor Gastón Giné


Unlike the other species of three-fingered sloths, the maned sloths are much larger with brown, fuzzy fur, and dark, hairless pads on their hands and feet (similar to the hands of two-fingered sloths).


maned sloth hand feet brazil
The hand and foot of a maned sloth. /Photos: Cecilia Pamich – The Sloth Conservation Foundation


They lack the iconic black mask around the eyes and male maned sloths do not develop a speculum.


maned sloth brazil

Instead, both males and females of this species have spectacular long black manes of hair that tumble down around their necks and shoulders.

Maned sloth brazil
Maned Sloth with a GPS backpack / Photo: Cecilia Pamich/ Sloth Conservation Foundation


Working together to save sloths

While our SloCo headquarters are based in Costa Rica, we are committed to conserving and protecting all 6 extant species of sloth that are found throughout South and Central America. 

Last month we were delighted to form an exciting new collaboration with Professor Gaston Giné and the Instituto Tamandua in Brazil to carry out important new research into maned sloth ecology.  


Maned sloth brazil
Professor Gastón Giné putting a GPS backpack on a maned sloth


Professor Gaston Giné has been researching maned sloths for over 10 years and much of what we know today about these sloths stems from the results of his work. He is a professor and researcher at the Applied Ecology and Conservation Lab of the Santa Cruz State University’s Biological Sciences department, and a research collaborator of the Instituto Tamandua.

Instituto Tamandua is a Non-Governmental Organization that works directly in the research and conservation of all Xenarthra species in Brazil (sloths, anteaters, and armadillos). Flavia Miranda, the founder and director of Instituto Tamandua, is the deputy chair of the IUCN Anteater, Sloth, and Armadillo Specialist Group.

Together with Professor Gaston Giné, Instituto Tamandua coordinates research into the maned sloths. 


Instituto tamandua
Flavia Miranda, founder of Instituto Tamandua, working with her team on a Giant Anteater in Brazil. Her research in the past 15 years has been very important for the conservation of sloths, armadillos, and anteaters, including the discovery of 6 new species of silky anteaters!/ Photo: Facebook Instituto Tamandua

Due to the ongoing impacts of the COVID-19 pandemic, funding for wildlife research and conservation has become scarce as government resources are directed elsewhere. This crisis has left maned sloth research and conservation projects in Brazil vulnerable and in danger of running out of resources. 

Thanks to the generous support of our donors, we are happy to have been able to provide funding for 10 new state-of-the-art GPS sloth backpacks that will be used by Gaston Giné and the Instituto Tamandua to continue their important work and better understand the ecological requirements, habitat preference, and movement patterns of this vulnerable species. 


Maned sloth brazil
Professor Gastón Giné releasing a maned sloth with a GPS backpack.

Team Sloth travels to Brazil 

In March 2021, SloCo founder Dr. Rebecca Cliffe travelled to Brazil with two other members of Team Sloth (Cecilia Pamich and Patricio Silfeni), to deliver the new GPS backpacks and learn more about the maned sloths.

They travelled to the Reserva de Sapiranga, near Praia do Forte, where they met up with Gaston, his son Caian, and professional tree climber (and expert sloth spotter) Cosme Guimarães a.k.a. Coy.


maned sloth reserva sapiranga
One of the rangers helping with the radio tracking of maned sloths.


For 7 days the team spent from sunrise until sunset hiking through the reserve searching for the elusive maned sloths. Some sloths were already being monitored by Gaston and needed to have their old backpacks replaced, but a lot of the sloths were new additions to the project.


Maned sloth brazil
It took almost 2 hours to spot this sloth. The signal from his radio collar was strong, but he was impossible to see until he moved into the open.


Every time a sloth was found, Coy would quickly scale the tree and carry the sloth safely down to the ground where important body measurement data would be collected by the team. The new backpack would be fitted, and a brightly colored ribbon would be attached to the back to act as a visual marker for identification.


Maned sloth brazil
This individual was identified as ‘Pablo’ and has a bright yellow ribbon on his backpack.


maned sloths brazil
 Neither the backpack nor the ribbon interfere with the activities of the sloth.

The sloths didn’t need to be anesthetized for the procedure as it was quick and simple, but it was necessary to use special Velcro mittens to cover the fingers and toes to prevent injury to the team.


Maned sloth brazil
Professor Gaston Giné and Dr. Rebecca Cliffe taking measurements. Velcro mittens are being used for safety.


During the course of the week, they managed to put GPS backpacks on 8 maned sloths (and mistakenly tried to capture a lot of termite nests that looked suspiciously like sloths)! 


maned sloth
Sapiranga reserve. The pale green dot was our base, and the yellow dots were the areas where we found the sloths.

Silent Rainforests

During their time in Brazil, the team were eager to learn more about the conservation problems being faced by maned sloths and to see how they could provide more help in the future.  

Having come from Costa Rica (where sloths are literally falling from the trees and climbing through people’s houses), they were shocked to discover how few maned sloths there were inhabiting the Brazilian forest reserves.

The maned sloths they found were also all very shy, hiding at the tops of the tallest trees and moving higher when they heard the sound of approaching humans. This is in stark contrast to the sloths in Costa Rica that tend to ignore people completely and often wander unfearfully into urban areas (and therefore get themselves into trouble). 


Maned sloth brazil


Finally, and perhaps most shockingly, the team were spooked by the eerie silence that followed them through the rainforest reserve where they were working. Upon entering a Costa Rican forest, you will reliably be greeted by the deafening hum of insects, screeching of parrots, and howling of monkeys. The rainforest feels and sounds alive. In the Reserva de Sapiranga of Brazil, the rainforest felt and sounded empty.  


atlantic forest maned sloth brazil
The Atlantic Forest (Mata Atlantica) has suffered the impacts of human development.


At first, they thought this difference was perhaps normal: the Atlantic forests are drier than the wet, humid rainforests of Costa Rica and so biodiversity is understandably different.  But as the week progressed, it became apparent that poaching and human disturbances are big problems in this region. The team stumbled across several different poaching traps, and they noticed platforms that had been erected in trees where poachers would hide. 


Why are maned sloths endangered? 

While it is unlikely that people go out specifically to hunt sloths, it is known that sloths are opportunistically poached for food in some areas (on a recent trip to Guyana we discovered that sloth meat is regularly sold in illegal markets there).

Over time, it seems likely that opportunistic poaching may have contributed to the shy nature and low numbers of maned sloths remaining in the wild. However, this is certainly not the only problem. 

Maned sloths have a very restricted range – they can only be found in a small strip of forest on the Atlantic coast of Brazil. Over 93% of these Atlantic forests have been lost in recent years due to deforestation for cattle pastures and plantations of sugar cane, cocoa, coffee, and eucalyptus.

maned sloth distribuition
Maned Sloth Distribution / Image: Instituto Tamandua – Ivy Nunes


As a result, maned sloths are severely affected by habitat loss, and the remaining forest reserves where they live are extremely fragmented and isolated. 


maned sloth habitat
The area surrounding the Sapiranga Reserve shows high levels of deforestation.

How to help the maned sloths

In order to safeguard a future for the remaining maned sloth populations, a multifaceted conservation approach that engages and empowers local communities is required. 

An important first step in the development of any conservation strategy is to properly understand the biological and ecological requirements of the species that you are trying to conserve. Without this knowledge, any attempt to mitigate the problems will likely be ineffective and short-lived. 

We are hopeful that the GPS technology that we have provided will help to increase current knowledge about maned sloths, and we look forward to developing further conservation strategies with our partners in Brazil to help maned sloths in the future. 


team sloth brazil
Cecilia Pamich, Cosme Guimarães, Gastón Giné, Rebecca Cliffe, and Patricio Silfeni after a full day of sloth scouting and backpacking.


We would like to say a special thank you to Professor Gastón Giné, Instituto Tamandua, Applied Ecology and Conservation Lab of the Santa Cruz State University’s Biological Sciences department, Prefeitura de Mata de São João, the rangers of Sapiranga Reserve, and all the lovely people that shared their knowledge and experiences with us throughout our trip!


maned sloth team


-Rebecca Cliffe

Founder and Executive Director


How much do sloths sleep?

How much do sloths sleep?

Sloths in the wild only sleep for 8 – 10 hours per day. The myth that sloths sleep all day long has manifested over decades of casual observation and a bad reputation.

Brown and Black Animal on Green Grass
Armadillos – close cousins of sloths – actualy sleep much more than sloths! / Photo: Steve Creek-Pexels

Sloths and sleep: the origin of the myth

The name “sloth” translates as a form of “lazy” in almost every language on our planet. Sloths have been burdened with their bad reputation since they were first described in the scientific literature in 1942 as “the lowest form of existence”.

Before the development of modern animal-tracking technology, scientists trying to understand wild animal behavior had to rely on opportunistic observations. They would simply watch and learn. While this basic approach may work for many species, sloths are unfortunately not one of them.

Sloths are slow-moving, shy, and secretive creatures that are almost impossible to observe for any length of time in the wild. They simply melt into the rainforest canopy and quickly become indistinguishable from the leaves and branches that surround them. They are masters of invisibility.

tales jungle
Photo: Suzi Eszterhas

We now also know that sloths have the same favorite sleeping spots that they will often return to throughout the day and night – interspersed by bouts of activity. A sloth might look like it hasn’t moved from the same place for several days, but it has probably been moving around during the night and has returned back to the same place for a rest. This pattern of behavior has previously tricked curious scientists into believing that sloths can sleep for days on end – something we now know isn’t true at all!

All of this, combined with the myth that sloths are “stoned” because of psychoactive properties in the leaves they eat, has garnered them with an unfair reputation for being lazy.


eating leaves
Three-fingered sloths favor leaves of the Cecropia tree. Dry leaves of Cecropias are smoked as a cannabis substitute due to the apparent psychoactive effects in humans. /Photo: Suzi Eszterhas

The problem of studying sloths in captivity

Due to the difficulties associated with studying sloths in the wild, the vast majority of research into sloth behaviour and sleep has been conducted on captive sloths.

It is becoming increasingly accepted that animal behavior in captivity can not be assumed to be the same for their wild counterparts. For example, in zoos and rescue centers, sloths don’t have to forage for the perfect leaves, worry about behavioral thermoregulation, or remain on high-alert for predators.


Rescued orphan sloth / Photo: Suzi Eszterhas


In addition, without the use of invasive and expensive methods, it is very difficult for an observer to differentiate between ‘sleep’ and ‘rest’. Taking these factors into account, it’s highly likely that the amount of time wild sloths spend sleeping is different from their wild counterparts.


sloth sleep
Photo: Suzi Eszterhas

How we measure sleep in sloths?

Sleep can be accurately measured by using an electroencephalogram (EEG), which records brain activity, and an electromyogram (EMG) which detects electric impulses occurring within muscle tissues.

These devices have been used on wild sloths in the past, but they are extremely invasive and likely disturbed the sloths normal behaviour.

Through our Sloth Backpack Project, we are utilizing the latest in micro-datalogger technology to record every tiny movement in wild sloths – from ascending and descending trees, to chewing and yawning. We are generating data that can be used to determine the sloths’ activity budget in a much less invasive way.

Using our backpack data, and comparing it with historical data collected by the use of EEG and EMG studies, we estimate that wild sloths sleep for 8-10 hours per day.

data loggers science
We use data loggers in the backpacks for the ‘Urban Sloth Project’

What is ‘inactive rest’?

While sloths don’t spend all day sleeping, this does not mean they are active either. They actually spend the majority of their waking hours in something that we like to call ‘active rest’ – they are not sleeping, but they are completely inactive and often have their eyes closed.

Sloths have the lowest metabolic rate of any non-hibernating mammal and the vast majority of their diet is leaf-based. Leaves themselves do not contain many calories, and due to their slow metabolism, the sloth’s caloric requirement per day is also very low (approximately only 100-150 calories per day!).

This means that sloths do not need to spend much time running around looking for food. Instead, they spend as much of the day as they can in an inactive state (which is easily perceived as sleep) in order to conserve energy and avoid detection by predators!


eating leaves
Do you eat salad? – 100g of lettuce contains 13-16 calories!



The true stories behind these famous baby sloth photos

The true stories behind these famous baby sloth photos

With a following rivaling that of the Kardashians, these baby sloths will never know just how famous they have become.

Note: Many of these baby sloths were photographed in rescue centers. SloCo is not a rescue center but we work closely with wildlife rehabilitation organisations on research and education initiatives to further our understanding of these unique creatures.

‘Mira’ – the world’s most famous baby sloth!

This is Miracle, or ‘Mira’ for short- she was found on a forest trail only a few hours old, with her umbilical cord still attached. She was rescued by a passerby and taken to the Sloth Sanctuary of Costa Rica. This photo was taken after she had been cleaned up and given a warm blanket to snuggle into.

You might not recognize this sloth, but scroll down to see her transformation!

Photo: Rebecca Cliffe


This is Mira around 8 months later. This photo was taken by Sloth Sanctuary volunteer Anne Goodall and was first used in the ‘Save Our Sloths’ fundraising campaign 8 years ago. The image went viral and has since appeared on everything, from bumper stickers to billboards.

Unfortunately, this photograph is also one of the most illegally replicated images (did you know that it is against the law to use somebody else’s photograph without their permission? Even if you paint or draw it!) Lots of people and companies sell merchanidse featuring this image without getting Anne’s permission!


Photo: Anne Goodall


Jewel was rescued as a baby with a broken arm by the Sloth Sanctuary of Costa Rica. Her arm was placed in a cast to aid with the healing process (today Jewel still has a bump in her arm where the bones were broken). Jewel and SloCo founder, Dr Rebecca Cliffe, have a close relationship. For a full year, Rebecca monitored every aspect of Jewels life in order to collect data for her PhD (including checking her body temperature every 3 hours for 8 continuous months – day and night)!



Esmeralda & Peanut

Esmerelda and her baby, Peanut, are wild three-fingered sloths living in the rainforests surrounding the Sloth Sanctuary in the South Caribbean. SloCo founder, Rebecca, alongside photographer Suzi Eszterhas, followed Esmerelda and Peanut every day for three weeks. In this well-timed photograph, Peanut is around 2 weeks old and is learning from mom which trees are the best for eating.

Photo: Suzi Eszterhas

Ali & Jessica: the most famous mom and baby!

Ali and Jessica miraculously survived after being hit by a car on Valentine’s Day 2015, with this photo becoming one of Suzi Eszterhas’ most popular pieces. Ali and Jessica are also available for symbolic adoption on our website. To capture this image, Suzi had climbed a tree and accidentally sat on a termite nest. The ants in her pants were worth it though!

Photo: Suzi Eszterhas

Ella, Shilo & Poko

Ella (left), Shilo (middle), and Poko (right) are three orphaned babies who became best friends during rehabilitation at the Sloth Sanctuary of Costa Rica. They would spend all day snuggled up together like this in a bucket in the baby nursery.

Photo: Suzi Eszterhas


Last (but certainly not least), we have Jessica again! In this photo, Jessica is around 5 months old, and her mother, Ali, is estimated to be over 25 years old.

Photo: Suzi Eszterhas