Tales from the Jungle | August 2022

Tales from the Jungle | August 2022

We’ve got exciting news this August! We have of course been up to our usual projects: reforestation, education, sloth crossings bridges, and research–and in addition, we’ve got a new team member, a new sloth, and a few new articles for you!

How concerning is “least concern”?

Four of the six species of sloths are classified as “least concern” by the International Union for the Conservation of Nature. The problem with this is that there is a lack of information about sloth population trends, meaning that the metrics used by the ICUN might be wrong in the case of sloths.

Check out this article written by Dr. Rebecca Cliffe addressing this issue, and how SloCo is working on a solution.



Wolaba Parade with the Kukula Kids club!

August is a very special month here in the South Caribbean, and each year our province of Limon in Costa Rica takes a holiday to celebrate our unique Afro-Caribbean culture, people, and heritage!



This year we were proud to march in the  Wolaba Parade, right down the main street of Puerto Viejo, with the Kukula Kids Club and our mascot, Siesta the Sloth.



Introducing Deborah!

Everybody give a big welcome to Deborah, our latest addition to the Urban Sloth Project! Debbie, as she is affectionately known to the tracking team,  is a beautiful two-fingered sloth (Choloepus hoffmanni) that lives in the same little forest as Mango and Maracuya near SloCo HQ. She was named after one of our dearest supporters, and we know she is going to be just as awesome.



Would you like to be one of our supporters too? Join our VIP community and receive monthly updates about the sloths we’re monitoring, plus photos, biographies, and more! In fact, here’s a little treat for you in the form of this beautiful illustration, which you can download here.


Welcome, José!

Say hello to our newest (human) member of the Urban Sloth Project, José Guzman García , with a degree in Biology with an emphasis on Ecology and Sustainable Development, who is joining our team to track sloths.

Jose is committed to generating changes in the community through science and conservation and is also a photographer, so if you get any extra special pictures of sloths in our VIP updates, you’ll know who to thank 😉

Welcome to crazytown, Jose!



How will global warming and climate change affect sloths?

Sloths are specially adapted to the constant temperatures of the rainforest, and–more so than most mammals–are deeply affected by changes in the ambient temperature.

This could leave them even more vulnerable to climate change than previously suspected; read more here about this research in Brazil, which studied and forecast how climate change will affect sloths and their habitat using some data collected and analyzed by Dr. Rebecca Cliffe.


sloth on the road
Sloths crawling on roads are vulnerable to dog attacks, roadkills or tourists’ harassment. / Photo


Tracking diaries #12

“I hand the tracking backpack off and take only the antenna and receiver, and begin to climb.

“Watch out!” calls Amelia from behind me. “You’re not in climbing gear!” I’m not; I’m in thick jeans, big rubber boots, and as many socks as I can put between me and any potential snakes that I might surprise while out traipsing through swamps. If I go tumbling off it’s a 15-meter drop to the crashing waves beneath us.” Continue reading…



Fails of The Month

Sick days are never over (Part III)

We did say welcome to Crazytown, right José? Well, the Caribbean baptism around here is that you get Dengue. Surprise! This tropical mosquito-transmitted disease (listed as one of the world’s Neglected Tropical Diseases by the WHO) really takes it out of you, but hey, we’ve all been there, so at least José is in good company. He made it through a LOT of papaya leaf juice, and we are happy to report he is better and back to sloth tracking.


-Sloth Team



How Concerning is “Least Concern”? Sloths and the IUCN Red List

How Concerning is “Least Concern”? Sloths and the IUCN Red List

What is the IUCN Red List?

Since 1964 the International Union for Conservation of Nature (IUCN) has kept a list of the world’s most threatened species. This Red List of threatened species has since become the go-to authority for the status of Earth’s flora and fauna, serving as a critical indicator of our world’s biodiversity. The status of a species on the IUCN Red List is how governments, NGOs, and conservation groups allocate resources and determine the policy that affects the natural resources needed for species to survive.

IUCN Red List Categories.

The most important part of protecting any species is knowing what needs protecting. The IUCN Red List information concerning species range, population size, habitat, ecology, exploitation, threats, and ongoing conservation actions are critical for species survival.

Sloths species by the IUCN Red List criteria

There are six living species of sloths on the planet. One of them is “critically endangered” (the pygmy sloth), one of them is “vulnerable” (the maned sloth), and the other four are listed as “least concern”. What, exactly, does that mean?

The problem with sloths

“Least concern”, according to the IUCN Red List, means that a species population is healthy and does not require any intervention on the part of humanity to ensure its continuation.

Wildlife rescue centers in Costa Rica receive two or three sloths per day, representing almost half of all admitted mammals. Authorities such as the Ministry of Environment and the National System of Protected Areas (SINAC) have declared that both sloth species (B. Variegatus and C. hoffmanni) living in the country are threatened and their populations declining.

In the past 13 years, we have seen first-hand how habitat loss and urbanization are causing the decline of sloth populations. This downturn has so far been witnessed but not yet measured, and is not confined to Costa Rica, but is likely at least as prevalent in other countries across South and Central America.


sloth on a powerline


Currently, there is no accurate data available on the status of sloth populations. We don’t know how many sloths there are, how many can or should inhabit any given area, or how fast populations are declining. There is not a single population estimate available for the majority of the sloth species, population trends are not being monitored and the geographical distributions of the different species are still unknown.


sloth on the road
Sloths crawling on roads are vulnerable to dog attacks, roadkills, or tourists’ harassment. / Photo: Rafacdul


If we don’t know how many sloths there are (or how many there should be), or even where they live, how can we make an accurate assessment of the state of the populations?


So, why are they listed as “least concern” if there is no data?

The IUCN Red List represents a global risk of imminent extinction; the chance that an entire sloth species could disappear from the planet tomorrow. This is a very valuable measurement, but can often be misunderstood with disastrous consequences. Some species can fall through the cracks entirely.

For example, the four “least concern” sloth species all have large population ranges covering many countries in South and Central America, as well as the Amazon rainforest. This means that there are a lot of individual sloths out there–and therefore the risk of all of these individuals becoming extinct overnight is relatively low.



maned sloth brazil
Maned sloths (Bradypus torquatus) are listed “vulnerable” / Photo: Cecilia Pamich


Unfortunately, the rate of population decline isn’t taken into account (because there is no data available to measure) and there hasn’t been an IUCN population assessment since 2013. In the case of sloths, the “least concern” status is based entirely on their wide distribution, as explained on the IUCN website:

“Bradypus variegatus is listed as Least Concern in view of its wide distribution including a large part of the Amazon forest, presumed large population, its occurrence in a number of protected areas, and because it is unlikely to be declining fast enough to qualify for listing in a threatened category.”


IUCN red list sloths least concern map
Population trend: UNKNOW  |  Source: IUCN Red List


Sloths move slower, reproduce slower, and disperse slower than other animals. If sloth populations become fragmented, isolated, or spread thin, they may not be able to recover in the same way as other mammals, and we have no idea what this critical population density might be or whether or not sloths are heading in that direction.

The case of the pygmy sloths

By comparison, the pygmy sloths in Panama are listed as “critically endangered”. They are found exclusively on one tiny island off the coast of Panama, and there are as few as 500 to 2000 pygmy sloths in existence. In fact, they are considered to be one of the most critically endangered mammals on the planet.


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

While that sounds alarming, it is also important to note that there have only EVER been a few pygmy sloths in existence. The size of the island constrains the population, and the sloth population there is actually stable.

So long as they are left alone on their uninhabited island, this species, while rare, is threatened more by global challenges such as global warming and would benefit more from broad rather than specific conservation measures.


pygmy sloth swimming
Pygmy sloth swimming, Isla Escudo, Panama. Just like most coastal zones, their habitat is threatened by climate change and sea levels. Photo: Suzi Eszterhas.


Despite this, pygmy sloths are eligible for a vast range of wildlife conservation and research grants and funding because of their “critically endangered” status.

Why absolute numbers do not tell the whole story

Meanwhile, sloth populations on the mainland are in decline, yet are burdened with the “least concern” status because of the very nature of their ecology. This means that it is virtually impossible to secure any funding for conservation or research.


sloth backpack research
Fitting a “backpack” with data loggers to a three-fingered sloth. Photo: Suzi Eszterhas


Without research, we cannot make a more accurate assessment of the population status, which means that we will not know when declining sloth populations reach a critical threshold until it’s too late.

The Great Sloth Census

Risk assessment for sloth populations hinges upon being able to take an accurate population census-a project that, before now, has defeated researchers by the nature of its impracticality. Sloths are very hard to find, and therefore to count.

For this reason, The Sloth Conservation Foundation has launched a groundbreaking new project to measure sloths in an area by measuring their scat, which is more reliably found than the sloths themselves, and training a Sloth Scat Detection Dog to help.


The dog will lead researchers to the sloth scat, the scat will tell us how many sloths are in an area, and long-term studies of the scat will yield information about population genetic diversity, sloth movements, territory sizes, and whether or not these populations are thriving or declining.

With this information, authorities such as the IUCN will have the data they need to decide if sloths are truly safe, stable, and of “least concern”.


-Dr. Rebecca Cliffe

Founder and Executive Director.