As a conservationist, I find myself thinking a lot about the word “diversity”. Concerning nature, the word is “biodiversity”, and we use it as a proxy for the health of ecosystems.
This refers not only to the types of plants and animals in an area, but also their genetic diversity, which produces the strongest, healthiest, and most adaptable organisms, as well as the types of landscapes they inhabit and adapt to. Diversity leads to resilience, and it is the reason we, and every other living thing on the planet exist. It is why we have fireflies that glow in the dark, and whales that sing across oceans, and feathery fractal ferns that drink water out of the air. It is the reason we have trees that live for millennia, oysters that make their own gemstones, and a fruit called a peacotum (which is what you get when you cross a plum with a peach with an apricot, and it’s every bit as awesome as it sounds).
Humans come up with a lot of strange ideas. Some of them are so strange that they make no sense at all out of context, and when I’m not pondering the etymology of the word “diversity” (from the Latin divertere, meaning “to face both ways”, for those of you curious) I wonder how humans came up with all these diverse ideas. Sometimes it helps to think of ideas as if they were living things. After all, they reproduce if we choose to share them with others, and they live in the context of other ideas, thoughts, and habits. We call this collection of self-replicating ideas a culture.
If a culture is an ecosystem of ideas, do the same rules for creating health, wonder, and resilience apply? What does it mean to cultivate diversity?
As a queer person, I find myself thinking a lot about rainbows. Not just because it’s Pride month and they’re everywhere, but what our flag represents: a spectrum of light, an infinite gradation of colors we have a limited vocabulary for.
Nature exists along a spectrum. This doesn’t always sit with our human desire to neatly label everything, because nothing natural exists in a homogeneous little box. Just as we like to label every species, sub-species, and variants of sub-species, we also like to label each other and ourselves. Lesbian, gay, bisexual, trans: we put a plus sign after LGBTQ because the diversity of human gender and sexuality was threatening to run out of alphabet before we ran out of identities－don’t worry, it’s not a test designed to fail the un-woke! It’s there because the grand spectrum of human potential has more words to describe it than we have letters to list.
Labels can be helpful even when they are not perfect. No one label strictly defines us, none fully captures us, and we all have a collection of labels for ourselves vying for relevance in any given situation. This collection of labels is called “intersectionality” (from the word “intersect”, meaning a thing that passes through or comes together with another). We usually talk about intersectionality when we are talking about privilege and people’s advantages and disadvantages in society. Sex, gender, race, class, religion, ability… these labels and more go into the variance within us; they make us who we are as much as our genetics shape our physical body, and much like our genetics, our intersectionality benefits greatly from a healthy dose of diversity.
As a scientist, I find myself thinking a lot about the truth. What is it, and how do we find it? How do we generate new ideas, and create a culture that promotes scientific discovery? Science is a process that concerns itself greatly with what is repeatable and relevant; what is true. We are human. The truth is our sex, sexuality, and gender exist along a spectrum, and we are as diverse in our internal identities as external ones. A culture that values those truths will reap the benefits of the people who live them－after all, we will never recognize the truth outside of ourselves if we do not begin by being true to ourselves.
To all of my fellow queer conservationists, scientists, and nature lovers; to all of our friends, families, and allies; and to everyone willing to protect and celebrate diversity and authenticity: Happy Pride!
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.
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)
Cecropiaspp.
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)
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Sloth fans in the United States – Mother’s Day is fast approaching! What better way to show your love and appreciation than by adopting a sloth in your mom’s name? We offer several different payment plans, and 100% of proceeds go directly towards funding our in-field sloth conservation efforts so it’s a double win!
Sloth babies fully rely on their moms to teach them how to survive in the canopy of the rainforest… just like your mom had to do when you were a baby (although hopefully with less time spent in a tree)! You can still get your virtual adoption package even if you order ON Mother’s Day, so don’t worry about being late.
See the sloths available for adoption by clicking here
The world is waking up to the palm oil crisis that has driven orangutans to the brink of extinction, but is boycotting palm oil really the answer? Unfortunately no, but that doesn’t mean that we are powerless.
Last week the UK supermarket chain Iceland shone the international spotlight on palm oil after its controversial Christmas TV advert was banned from British television. The advert, which depicts an orangutan hiding in a child’s bedroom after loggers destroyed his rainforest home, has now been watched over 30 million times online making it one of the most successful Christmas adverts ever created. Similar to the anti-plastic movement that is sweeping across the world, this advert has stimulated an uproar against the palm oil industry. While it has been overwhelmingly successful at raising awareness of a very important issue, fears are growing as increasing numbers of people are demanding a boycott on palm oil. This is dangerous.
Palm oil is used in approximately 50% of everything that we buy, ranging from food and shoes to cosmetics and cleaning products. It is everywhere and the demand is huge. Consequently, palm oil plantations are responsible for the majority of Malaysian and Indonesian deforestation, with a football pitch-sized area of forest being cleared every 25 seconds in Indonesia alone! However this is not just an issue affecting Asia. Palm oil plantations are also springing up in place of the sloths rainforest habitat in South and Central America, further adding to the ecosystem destruction occurring due to crops such as soy, bananas and animal agriculture.
Boycotting palm oil, however, doesn’t mean that manufactures will simply remove oil from their products all together. It simply means that they will be forced to replace it with a different kind of vegetable oil. Unfortunately, palm oil is already the worlds most productive oil crop. All alternative oils such as soybean and rapeseed require up to 10 times more land to produce the same amount of product – increasing demand on these crops would be even worse. In addition, boycotting palm oil will drive the price down, consequently increasing the demand for use in biofuel and livestock feed, particularly in countries such as China and India.
So what can we do? Thankfully the answer applies to all aspects of consumerism, and will have benefits for species and habitats globally (including sloths!): sustainable shopping. Think carefully about the products that you buy because as the consumer, you have the power. Only choose products from manufacturers and retailers who use ingredients from sustainable, certified, legal and deforestation-free sources. They exist, you just have to know which ones to look for! We know this sounds like a lot of hard work – who has time to read every label and search online for every product that you want to buy? But the good news is you don’t have to! There is a wonderful (and free!) bar-code scanning app called Giki that will do all of the hard work for you. Just scan the product that you want to buy and it will tell you all of the information you could ever want to know about that product. Whether it’s local pollution, global climate change, conservation, animal welfare or health, it will give you everything that you need to make an informed decision! Thankfully, using this app will also help you to avoid fruit and produce that is contributing to the sloth deformity epidemic in Costa Rica by way of rampant pesticide usage and forest fragmentation. It’s a win for everybody!
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offer several different payment plans, and 100% of proceeds go directly towards funding our in-field sloth conservation efforts so it’s a double win!
