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

Love avocados? Thank the giant ground sloths!

Love avocados? Thank the giant ground sloths!

Did you know that we can thank giant ground sloths for the avocados we have today? Giant ground sloths were one of the few ancient herbivores large enough to swallow avocados whole, thus serving as an important seed disperser for these delicious fruits that we know and love today!

Illustration of the giant ground sloths by Robert Bruce Horsfall/Source: Wikimedia Commons


Many plants, especially in tropical ecosystems, have evolved to rely upon animals to spread their seeds. Only extra-large herbivores such as the giant ground sloths had the ability to swallow avocado seeds whole, meaning that they could carry them around in their digestive tracts and eventually defecate them far away from the parent tree!

Evidence of these ancient symbiotic (mutualistic) relationships can still be seen today. For example, honey locust trees (Gleditsia triacanthos) have large sweet-smelling seed pods that were eaten by megafauna. They also have big, intimidating spikes on their trunks which likely served as an important defense against these giant herbivores. Now a popular city tree due to their ability to withstand poor conditions, modern versions of honey locust trees have been bred without spikes although their supersized seed pods still litter our bustling city streets.

Seed pods and thorns of the honey locust tree (Gleditsia triacanthos). Although seemingly powerless against modern tree dwellers these spikes likely served as vital protection against the large herbivores of the Pleistocene./Images:

How big were the giant ground sloths?

These ancient ancestors of modern-day sloths truly lived up their name. Like bears and anteaters, they had the ability to stand on their hind legs, making them the largest bipedal mammals to have existed. Over 100 species of giant ground sloths lived throughout North, Central and South America, ranging in size from the formidable Megatherium americanum which towered 3.5 metres tall (12 feet), and weighed up to 4 tons, to the considerably smaller 90-kg (200-lb) Cuban Megalocnus. 


Skeleton of the giant ground sloth (Megatherium americanum)/Source: Wikimedia commons


The giant ground sloths of North America disappeared around 11,000 years ago and their South American cousins followed suit around 10,200 years ago. However, amazing fossil evidence from 2007 revealed that 200-lb Megalocnus were still lumbering around the islands of Cuba as little as 4,200 years ago!


Skeleton of the considerably smaller Cuban ground sloth (Megalocnus rodens)./Source: Wikimedia Commons

Why did the giant ground sloths disappear?

Like many of the memorable megafauna of the last ice age, the exact cause of their extinction remains somewhat murky. Megatherium fossils have been found with cut marks on them, suggesting that ancient humans did consume these giant beasts. However, humans and the giant ground sloths of Cuba coexisted for a period of about 1,000 years. It is likely that a combination of over-hunting and/or climate change led to their demise.


Artist’s interpretation of the giant ground sloth (Megatherium) of the Pleistocene and two Glyptodon./Source: Wikimedia commons


Although the last of the giant ground sloths disappeared around 4,200 years ago, modern sloths carry on their legacy. Scientists have hypothesized that modern-day two and three-fingered sloths evolved from two distinct lineages of extinct giant ground sloths. In other words, although not closely related, two and three-fingered sloths both evolved independently to live in trees, in a process called convergent evolution. However, recent genetic evidence suggests that the species of sloths alive today may have evolved from an ancestor that was comfortable on the ground as well as in the trees.


The future of avocados

Without their ancient seed dispersers, the future of avocados is now in our hands. Unfortunately, avocado trees are quite sensitive to changes in temperature and water. A single avocado requires 60 gallons of water to grow. Fluctuations in rainfall and temperature due to climate change are causing shortages of these lucrative crops. Moreover, the expansion of avocado farms in Mexico has led to the destruction of pine and fur forests thus affecting monarch butterflies. The high demand for avocados has even caused gang warfare to break out in areas such as the Michoacán state of Mexico, where almost 80% of the US’s avocados come from.

Also known as “alligator pears” avocados became popular due to the targeted marketing efforts of Californian farmers in the 1990s./Image:

A sustainable future for avocados, means growing them in places where water is plentiful using agricultural methods (such as agroforestry) that make space for biodiversity.


-Katra Laidlaw



Five-ton giant sloth lived in Costa Rica seven million years ago!

Five-ton giant sloth lived in Costa Rica seven million years ago!

A giant sloth weighing five tons and whose height could exceed twice that of a human being was part of prehistoric Costa Rica seven million years ago.

A group of paleontologists is working hard to determine the characteristics of this giant sloth to see if it corresponds with previously described species – or whether it is completely new to science!

This is part of a project that started in 2003 in San Gerardo de Limoncito, Coto Brus, about 11 kilometers from San Vito. In this area, the researchers searched for bones and fossils of different species.

For more than a decade, Ana Lucía Valerio, coordinator of Geology at the National Museum, and César Laurito from the National Institute of Learning (INA) searched and analyzed more than 2,600 samples of bones from dozens of different species that appeared throughout the expeditions.

giant sloth
The bones found correspond to giant sloths similar to those in this image, whose height can easily exceed twice that of a person. Illustration: Franklin Rodríguez

“When I decided to go for paleontology, no one cared for something to appear here. Venturing out to find mammals was unthinkable. They told us ‘you are looking for little bones, it is not important’, but the finding makes the world look again and say ‘something is happening here, something we did not expect and that is changing the vision of biological exchange'” Laurito explained.

This region is important because it provides further proof that Central America served as a bridge for animals to cross from South America to North America and vice versa. 

“We are talking about something very old. The Isthmus only closed about 3.5 million years ago, but these sloths lived seven million years ago. So how did these giant animals from South America get to southern Costa Rica if they had no adaptations for swimming? It is possible that for a time there was a pass, a land bridge, for these animals to cross. This passage could exist for a short period of time, but for paleontology, a short period of time could be a million years ”

“In other words, species from South America are appearing much earlier than expected – by about four million years” he clarified.

Describing the sloths:

In recent years, Valerio and Laurito have described many different species of prehistoric horses, camels, armadillos, and other types of mammals on Costa Rican soil.

However, they had a problem with the sloths’ material as they had no way to compare it. This type of research in paleontology is very new in Costa Rica, and so they formed a collaboration with Ascanio Rincón, head of Paleontology at the Venezuelan Institute of Scientific Research, who has been studying these prehistoric giants for many years.

Rincón helped to complete the next part of the analysis: determining what kind of sloths they are. All of the bones were found at the same site, but they accumulated during different years of searching.

“There is no record of these animals in North America until much later. What prevented them from crossing? Or what did they find here that made them stay longer without moving?” Rincón wonders.

For this new analysis, all bones must be photographed, measured, analyzed, described and compared with the bones of other giant sloths. After all of this, important aspects of these populations can be determined.

giant sloth found in costa rica
The Venezuelan paleontologist Ascanio Rincón (left) is in the country to collaborate with the research of Ana Lucía Valerio Zamora and César Laurito Mora, who have spent years studying the paleontology of fossils found in Coto Brus. In the photograph they present the ankle bone of a giant sloth. Photo: Rafael Pacheco

“Now we have to do the hard work, which is to compare it with the rest of the 14 or 15 genera that exist and determine who it resembles the most and who it resembles the least and see if we are dealing with a new species,” said Rincón.
This is not easy. It is very difficult to find complete bones and so they only have small samples from which to draw conclusions.

“This is not how it looks in the movies. Not that it was just brushed off a bit and there it all appeared. We had to chop very hard rocks to be able to remove this. It took a lot of strength, a lot of searching, and sometimes bones of some species appeared, while sometimes other bones of other species. What we have today was put together and gathered over several years ”, Laurito indicated.

Rincón added: “It is hard to be able to know what is happening with only 15% of the body; how to put this puzzle together? In this case, we do have material from various types of bone that help us to better understand the panorama”.

The researchers reported that at least three individual sloths have been found as they discovered three bones of the same type but different sizes (ages). This indicates that these giant sloths may have traveled in a herd or as a family.


giant sloth
These are some of the giant sloth bones scientists are analyzing. Photo: Rafael Pacheco

What do we know about this animal?

Although it is difficult to properly visualize what these extinct sloths looked like, scientists do have some ideas!

For example, it is known that they walked on the soles of their back feet and on the knuckles of their hands. The front claws were very strong and were probably used for digging. Furthermore, due to their massive size and weight, these sloths probably did not climb trees!

Their teeth were so strong they could feed on wood and other hard materials. These teeth had a remarkable ability to regenerate from the wear and tear that was incurred when chewing. In fact, chewing was essential to prevent the teeth from overgrowing and causing problems!

Giant sloths are known to have been social animals, possibly living in large herds or family groups.


Giant Ground Sloths lived in North and South America and went ...

The importance of the discovery

Within these discoveries there could be now-extinct species that are new to science.

“The fossil hunter does not kill his prey, he resurrects it. We resuscitate that dam that we are looking for in order to get to know it and for people to know it” said Rincón.

Why is this important? Rincón was emphatic: “This type of knowledge helps us to understand who we are, where we came from, and it gives identity to the Isthmus. We cannot judge a book by its last page, we must see what comes before, and that is why it is necessary to study paleontology ”.

-Source: Diario La nación Costa Rica

With a little help from my friends: sloths, moths and algae

With a little help from my friends: sloths, moths, and algae

Sloths are naturally solitary animals, but they are not all alone up there in the canopy. In fact, sloths have an entire ecosystem living in their fur made up of different species of algae, fungi, moths and insects. That’s millions of organisms for company!

Sloth hairs have a unique structure that involves microcracks. These microcracks create the perfect environment for algae and fungi to thrive.

sloth hair friend
Three-fingered sloth hair under a microscope! You can see the microcracks and green algae. 

The microorganisms living in these cracks were investigated by biologists for the first time in 2014, and they discovered species of algae and fungi which have not been found anywhere else in the world!

These fungal species are currently being investigated by microbiologists, parasitologists, and oncologists alike, as some strains are showing uses in treatment for malaria, chagas disease, and even breast cancer.

sloth friend algae
Different strains of green algae found in sloth hair.


Good friends that provide camouflage against visual predators

Sloths have a mutualistic ectosymbiotic relationship with the ecosystem growing on their backs. The fungi, algae, and moths greatly benefit from this relationship as they have a habitat to thrive in. The sloth benefits because these organisms are key to the sloth’s best defense against predation – camouflage.

Hunters that use their sense of sight, such as raptors, will often bypass sloths when searching for prey because the growth of algae and fungi give the sloth’s fur a green tinge, allowing them to blend into the rainforest canopy. This, along with the sloth’s slow movement and other creepy crawlies that make their home in the sloth’s fur, means that sloths usually go undetected by predators who hunt by sight.

sloth selfie distance
Sloths blend in perfectly with the trees they live in.

Sloths smell like the jungle

But what about the predators that hunt by scent? Sloths don’t produce any body odor at all! The growth of this ecosystem in their fur means that sloths look like the trees, they smell like the trees and they even move like the trees (very slowly). 

sloth moths
Sloths look and smell just like the jungle that surrounds them. / Photo: Suzi Eszterhas

Sloth moths

Sloth fur is also the perfect home for six different species of sloth mothsBradypodicola hahneli, Cryptoses choloepi, Cryptoses waagi, Cryproses rufipictus, and Bradypophila garbei.

These moths are exclusively found living in sloth fur and can coexist together on the same sloth. Studies have shown that generally, the three-fingered sloth carries more moths than a two-fingered sloth, with one study recording more than 120 moths in a three-fingered sloth’s fur.

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

When the sloth descends from the canopy once a week to go to the toilet, the moths will crawl from the sloth’s fur onto the fresh sloth poop to lay their eggs. This is the ideal place for these eggs to hatch, as the larvae are coprophagal which means they feed on the sloth poop. Once the larvae develop into moths, they will fly up into the trees to find an appropriate sloth to call home. And thus, the cycle begins again.

Without the sloth, these moths could not exist. The sloth gives these creatures a home and provides them with food – moths have a proboscis rather than a jaw, which they use to suck up the moisture from the sloth’s eyes and secretions from the sloth’s skin.

poop sloth moths
A sloth will only poop on the ground – a ritual that sloth moths have taken advantage of! 

The circle of life!

Sloth moths can sometimes also attract unexpected visitors. Recent footage has emerged from Cahuita National Park, Costa Rica, showing a juvenile Capuchin monkey picking and eating the moths from the fur of a two-fingered sloth! 

This incredible sight had never been captured on film before, and it is not a behaviour that we were aware of! How often does this happen in the canopy while no humans are around to watch? Something similar has also been observed with a brown jay picking the moths from the fur of a three-fingered sloth!

So, if you ever see a green sloth covered in moths, know that that is a very healthy sloth with lots of ‘creepy crawlie’ friends!

Sloth Genetics: a surprising twist

Sloth Genetics: a surprising twist

Six years ago, SloCo Founder Dr. Rebecca Cliffe launched a major research project into sloth genetics in Costa Rica. She started this project because she was concerned with the number of wild sloths in the South Caribbean region that are being born with debilitating birth-defects (missing fingers/toes, malformed ears, and misshapen limbs), and she wanted to know what was happening.

The results of this project have now been published and they reveal an unexpected situation with far-reaching implications for future sloth conservation and rescue efforts.

Cover image created by Dr. Chloe Robinson 
sloth genetics hair sample
Dr. Rebecca Cliffe, a sloth biologist, collecting hair samples from an anesthetized three-fingered sloth for a similar genetic study. Photo by Suzi Eszterhas


In order to find out what is really going on, we collaborated with Dr. Chloe Robinson, Swansea University and the Sloth Sanctuary of Costa Rica to undertake the first exploratory investigation into sloth population genetics in Costa Rica.

We collected hair samples from 98 two-fingered sloths (Choloepus hoffmanni) that originated from different regions throughout Costa Rica and used microsatellite analysis to look at the population genetics.

Infographic by Dr. Chloe Robinson


We made 3 important discoveries regarding sloth genetics:

Finally, after many years of hard work, we are delighted to announce that the results of this research have now been published as an open-access article in Evolutionary Applications. We have summarized the results below.

We were able to identify 4 genetic groups of two-fingered sloths in Costa Rica (this is similar to having 4 genetic origins). If you are familiar with Costa Rican geography, these are the groups that we identified:

  • The West – sloths from the San Jose region
  • The North – includes sloths from areas surrounding Guápiles and further North
  • The East – sloths from within Limón city and surrounding areas
  • The South East – the South Caribbean region ranging from Bananito down to Manzanillo and BriBri.


sloth genetics costa rica


It is important to note that there are probably many more groups than the four that we identified, but for logistical reasons we could not collect samples from sloths spanning the whole country. Our results only reflect the areas where we were able to focus our sampling efforts.

1) Sloths in the North are genetically distinct.

Sloths in the ‘North’ group were found to be genetically very distinct when compared to the other populations. This means that sloths in this region are substantially different from sloths in other areas of Costa Rica that we sampled. We suggest that it may be important to recognize this sub-population as a separate unit for management and conservation purposes.

A distinct sub-population like this is sometimes referred to as an Evolutionarily Significant Unit (ESU).


Figure taken from the publication. Terrain map of sample sites in Costa Rica where 98 individual Choloepus hoffmanni sloths were hair sampled for genetic analyses.


2) Sloths in highly urbanized areas are inbreeding.

Sloths in the ‘West’ group have higher levels of inbreeding, (when individuals who are closely related reproduce). This may not be surprising when we consider that sloths here are restricted to living in severely fragmented forest pockets within the highly urbanized San Jose region.

This suggests that we need to focus more conservation and research efforts in this region to better understand the long‐term effects of habitat fragmentation.

sloth genetic deformities
This baby sloth was born with just one digit on each limb. The survival rate of individuals like this is very low.

3) Sloths have been moved around by humans.

Finally (and perhaps most importantly), we discovered that sloths in the West, East and South East groups were all surprisingly similar. This close relatedness between sloths living on opposite sides of Costa Rica is an unexpected and potentially concerning result. Particularly when we consider the vast geographical distance between these populations and the inability of sloths to travel long distances.

Interestingly, sloth populations in the South Caribbean were found to be more genetically diverse and had high levels of admixture (which means lots of sloths from lots of different origins have been reproducing with one another).

All of this points towards the translocation of sloths by humans in Costa Rica, where individuals have been removed from their areas of origin and released somewhere else.


sloth genetics costa rica

How could this happen?

When we consider that approximately 3 – 4 sloths are admitted into rescue centers every single day in the South Caribbean, it is not surprising that some of these animals may have originated from further away.

The translocation of wildlife was particularly prevalent in earlier years when there were not as many rescue centers who knew how to properly care for sloths. The government of Costa Rica (and in one case a national airline) would regularly deliver inured sloths from all over the country to the Sloth Sanctuary on the Caribbean Coast as they were considered to be the only experts in sloth rehabilitation at the time.

This has since changed. In the last decade there has been an explosion of new rescue centers. Costa Rica now has more rescue centers per square mile than any other country, with over 250 registered facilities currently rescuing and rehabilitating wildlife! The current abundance of rescue centers means that the cross-country translocation of sloths may be less of a problem, but the regulation of release protocols is more difficult.


Is this mix-up of sloth genetics a bad thing?

We do not know, but it could be.

You may think that high levels of genetic diversity are considered to be a good thing in wildlife conservation – and this is true. Increased genetic diversity means less inbreeding has occurred and gives populations a stronger ability to adapt when faced with change.

However, as with most things, it is rarely that simple. Mixing individuals from different genetic backgrounds can also have a dangerous effect on the health and viability of populations through a process called ‘outbreeding depression’.

loss of local adaptations


Animals often have unique genetic adaptations that help them to survive in the particular environment in which they live. For example, sloths that live in cold montane regions have adaptations to cope with a colder climate, including longer, thicker, and darker hair compared to their lowland counterparts. By moving individuals around, these adaptations can be lost and the inter-breeding that occurs can negatively impact the health of these populations.

A similar situation was recently discovered in orangutans that were reintroduced to the wild from rescue facilities in Borneo without knowledge on the genetic background and subspecies status of the individuals.

In line with this, there is an emerging global awareness of the need to consider the genotypes of animals prior to release, including official guidelines and recommendations set out by the International Union for the Conservation of Nature. However, in Costa Rica, there are currently no existing protocols or legislation to encourage or regulate this practice.

Sloths living in lowland tropical rainforests have different features compared to sloths of the same species that live in mountainous regions / Photos: Suzi Eszterhas

What does all of this mean for sloth conservation?

The genetic diversity between separate sloth populations have emerged over the course of millions of years. By mixing together populations that perhaps haven’t been in contact for millennia, we are potentially causing irreparable changes.

It may be that inter-breeding sloths from different genetic origins has no negative effects at all. But what if it does? Suddenly, we will have inadvertently compromised the viability of wild sloth populations and no amount of conservation work can ever reverse that damage. 

Is it worth the risk?

This discovery means that rescue facilities in Costa Rica should consider the genetic background of rehabilitated sloths when planning future reintroductions. Sloths should be released in the areas where they originated from whenever possible.

This will undoubtedly present a challenge for overburdened and underfunded rescue centers. Combined with increasing pressure for post-release monitoring, it may seem impossible for animals to be returned to the place of origin and simultaneously tracked to ensure survival.

Furthermore, it may not be possible to always return an animal to the place that it came from. There may be a lack of suitable habitat in that area, or the rescue center may not have accurate records on where the animal was originally found (rescued animals often pass through several pairs of hands before arriving at a rescue facility, and tracking down the origin can sometimes be difficult).


What can we do moving forward?

There will be no convenient solution, but we must work together to find one.

Ultimately it is going to require increased government assistance, funding and collaboration between different rescue centers and release sites throughout Costa Rica. It will require increased transparency and improved record keeping in order to ensure that rescued sloths are returned to where they were found. 

Furthermore, it will require the preservation of habitat where these distinct sloth populations are living (since they cannot be brought elsewhere).

When sloths were first being transported around the country, we didn’t know better. Now we do. Equipped with this new knowledge, we can now ensure that our actions to help them will truly lead to a long and healthy future for sloth populations in Costa Rica.


sloth genetics


~ Dr. Rebecca Cliffe

Founder and Executive Director 

8 Facts You (Really) Didn’t Know About Sloths

8 Facts You (Really) Didn’t Know About Sloths

The internet is full of ‘facts’ about sloths. You will be surprised to know how much of this information is untrue.

For example, many people believe that the leading cause of death in sloths is when they fall out of the tree after mistaking their own arms for tree branches. This ‘fact’ was actually invented in the book ‘A Hitchhikers Guide to the Galaxy’ and is definitely not true. Because so little is known about sloths (and much of what we do know is admittedly bizarre), people are eager to believe whatever nonsense they hear or read on the internet

Here we bring you eight surprising things that you (probably) didn’t know about sloths!

1- Do sloths have nails? Or are their claws made of bone?

Well, it’s somewhere in between. While sloth claws look like overgrown nails, they are actually formed by elongated and curved distal phalange bones protruding from their limbs. These bones are covered by a sheath of the same material that makes up our fingernails and hair (keratin).

Three-fingered sloth skeleton showing the claws/fingers.

Sloth claws achieve their shape and sharpness by constant use climbing trees. If they get broken or damaged, sloths can actually regrow the claws thanks to their low metabolic rate (in a similar way to when reptiles regrow their limbs). However, the claws will rarely regain their original shape, often growing back deformed. In the wild, this can put the sloth at a great disadvantage as their claws are vital for life in the canopy.

facts sloth toed finger nails Suzi Eszterhas
A two-fingered sloth with deformed fingers from a previous injury. Photo: Suzi Eszterhas

In captivity sloths often have overgrown claws which curl painfully into the pads of their hands and feet, making climbing and feeding difficult. In these cases, the underlying bone is the same size, but the fingernail sheath is overgrowing because it isn’t being worn down by climbing as frequently or as intensely as their wild counterparts. Overgrown claws are much easier to break, and this is why sloths living in captivity often have damaged or deformed claws!

Sloths in captivity often have overgrown nails on their fingers and toes

2- There is a Greek Sloth Goddess

The Greek goddess Aergia (pronounced AIR-gee-a) is the personification of inactivity or slothliness. She guards the Court of Hypnos in the Underworld, alongside the Gods of quietness and forgetfulness. As she is the goddess of laziness, she spends most of her time sleeping and has servants do her work for her.

Unfortunately, wild sloths do not have staff to do their bidding and will only sleep 7-10 hours per day – this is around the same as a human! To put things into perspective, sloths will often share their trees with troops howler monkeys who sleep for up to 20 hours each day.


Aergia (Greek: Ἀεργία, “inactivity”) / Image:

3- ‘Give me a lever long enough, and I shall move the world’ – Archimedes

Sloths are often described as ‘nothing but bone, skin, and fur’ which is not inaccurate but does gives the wrong impression of our robust friends. An adult sloth is approximately three times stronger than the average human, which is the result of some clever anatomical architecture.

Skkiny sloth facts suzi eszterhas
Sloths are very skinny underneath their thick fur! Photo: Suzi Eszterhas

The sloths’ evolutionary mantra has been to reduce energy consumption in every possible way – more muscle requires higher energy consumption; as a result, sloths have 30% less muscle mass than other similar-sized mammals. The fibers of these muscles are organised differently to ours, being arranged at an angle rather than parallel to the length of the muscle, which makes their muscles pound-for-pound more powerful than ours.

strong sloth
A sloth can fall asleep while dangling from a tree branch /Photo: Suzi Eszterhas

What does Archimedes have to do with this? The anatomical organisation of the muscles themselves also contributes to their disproportionate strength. Sloth muscles appear to work on a sort of lever system – resulting in an immense volume of pulling strength with very little muscle mass and expending very little energy.

facts nails
Even tiny babies are super strong!

4- Sloths can pull but they can’t push

Sloth muscles are specialized for suspensory ‘upside-down’ locomotion; they produce strong pulling and gripping motions, with very little strength for pushing. This is one reason why sloths cannot walk across the ground like a quadruped; the muscles responsible for ‘pushing’ can not produce enough force to lift their bodies off the ground for efficient locomotion (not to mention their claws also make this very difficult) and it takes an enormous amount of energy which the sloth cannot afford to lose.

Sloth road
Sloths move on the ground with a crawling motion, rather than walking / Photo: Suzi Eszterhas

This is a similar concept to a crocodile’s bite force – they have incredible force in closing their jaws, but even a strip of tape is enough to prevent them from opening their mouths.  In an ideal environment, sloths would never have to travel in this way, however, due to deforestation, they are having to come down to the ground more and more often.

5- Two-fingered sloths have black fangs

Sloths are hypsodonts, meaning that like rabbits and horses, their teeth grow continuously throughout their lives. The two-fingered sloths have four razor-sharp pseudo-canines, two on top and two on the bottom. The slight overbite causes the top pair to grow in front of the bottom pair and constantly rub against each other. Every time a two-fingered sloth opens its mouth their fangs sharpen up, maintaining two pairs of very sharp teeth.


As their diet consists of only leaves, they also ingest a lot of tannins. Tannins are the substance that gives dead leaves their brown color and will turn rivers orangey-brown during certain seasons. Sloths do not have the protective enamel layer over their teeth as we do, so the high concentration of tannins dyes their top fangs black, however, their bottom pseudo-canines remain white due to the constant rubbing against their top teeth.


sloth skull teeth facts
By our own experience, we can tell you: you don´t want to get bitten by a sloth!

6- Three-Fingered Sloths have more neck vertebrae than a giraffe.

From humans to giraffes, to mice: all mammals have seven neck (or ‘cervical’) vertebrae. There are only a couple of mammals who are exceptions to this rule – sloths and manatees. Three-fingered sloths have nine cervical vertebrae, while both two-fingered sloths and manatees have only five.

sloth neck vertebrae

Now, if you are blown away by these facts and choose to do your own research, there is a debate as to whether the three-fingered sloth has eight or nine cervical vertebrae, and whether the two-fingered sloth has five or six. This discrepancy is due to a dispute on what differentiates neck vertebrae from thoracic vertebrae.

These extra cervical vertebrae allow three-fingered sloths to turn their heads through 270° which, following the sloths’ evolutionary effort to reduce energy consumption wherever possible, is a clever energy-saving tactic.

sloth turns head 270
A three-fingered sloth can see the world the right way up, despite being upside down! / Photo: Suzi: Eszterhas

No one is too sure of the evolutionary purpose of two-fingered sloths having only 5 cervical vertebrae, however, it has been suggested that this abnormality allows two-fingered sloths to tilt their heads all the way backward. This can be useful when trying to access hard-to-reach leaves on the tips of branches!

Sloths utrning their heads facts

7- Sloths can float thanks to their stomachs

A sloth’s torso is two-thirds stomach. This very large, four-chambered stomach is mostly full of gas from fermenting leaves, which acts as a floatation device. There is a common myth that it is impossible for a sloth to drown because of this gassy stomach (which is not true), but these built-in floaties are certainly an advantage in the water.

Three-fingered sloths are very good swimmers. In fact, they can travel three times faster in the water than on land! It has been suggested that the sloth’s extra cervical vertebrae help to help keep the sloth’s nose above water while swimming. 

sloth floating
A Pygmy three-toed sloth swimming in a mangrove forest Isla Escudo de Veraguas, Panama / Photo: Suzi Eszterhas

8- Ribs… ribs…. ribs… and some more ribs

Unlike vertebrae, the number of rib pairs in mammals varies between species. If you take a look at the two-fingered sloth skeleton pictured, you can see that there looks to be a disproportionate number of ribs – there are 21 pairs! This is the largest number of ribs in any mammal, with humans having 12 pairs and whales only having nine!

In all animals, rib cages function to protect our internal organs. A sloth’s stomach can occupy up to 30% of the sloth’s body weight – a stomach this large needs some extra support and protection! Sloths regularly fall from the canopy (they can fall from 100 feet in the air and survive!) and so having tough internal hardware is important! 


Approximate size and location of the sloth stomach /Photo: skull unlimited

Three-fingered sloths also have multiple unique fibrinous adhesions that effectively anchor their abdominal organs against the lower ribs. These evolutionary ‘coat hangers’ support the weight of the sloth’s stomach and bowel whilst the animal is hanging inverted, preventing the lungs from being squashed and facilitating breathing.

-Amelia Symeou

Ecology Coordinator


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Genética de perezosos: un giro inesperado

Genética de perezosos: un giro inesperado

Hace seis años, la fundadora de SloCo, Dra. Rebecca Cliffe, lanzó un importante proyecto de investigación sobre la genética de perezosos en Costa Rica. Este proyecto se inició debido a la cantidad de perezosos salvajes en la región del Caribe Sur que nacen con condiciones genéticas debilitantes (falta de dedos en manos y pies, malformaciones en orejas y extremidades deformes).

Los resultados de esta investigación ya se han publicado y revelan un escenario inesperado, con implicaciones de largo alcance para futuros esfuerzos de conservación y rescate de perezosos.

sloth genetics hair sample
Dr. Rebecca Cliffe, bióloga con especililización en perezosos, recolectando muestras de pelo de un perezoso de tres dedos bajo anestesia para un estudio genético similar al presente/ Photo: Suzi Eszterhas


Con el fin de averiguar qué está sucediendo, colaboramos con la Dra. Chloe Robinson, la Universidad de Swansea y el Sloth Sanctuary para llevar a cabo la primera investigación exploratoria sobre la genética de la población de perezosos en Costa Rica.

Recolectamos muestras de pelo de 98 perezosos de dos dedos (Choloepus hoffmanni) de diferentes regiones de Costa Rica y utilizamos análisis de microsatélites para observar la genética de la población.

genetica perezosos

Hicimos 3 descubrimientos importantes con respecto a la genética de los perezosos:

genetica perezosos

Finalmente, después de muchos años de arduo trabajo, nos complace anunciar que los resultados de esta investigación ahora se han publicado como un artículo de acceso abierto en Evolutionary Applications. Hemos resumido los resultados a continuación.

Pudimos identificar 4 grupos genéticos de perezosos de dos dedos en Costa Rica. Si está familiarizado con la geografía costarricense, estos son los grupos que identificamos:

  • Oeste: perezosos de la región de San José.
  • Norte: incluye perezosos de áreas que rodean a Guápiles.
  • Este: perezosos de la ciudad de Limón y sus alrededores.
  • Sureste: la región del Caribe Sur, desde Bananito hasta Manzanillo y BriBri.

genetica perezosos costa rica

Es importante señalar que probablemente hay muchos más grupos que los cuatro  identificados en este estudio, pero por razones logísticas no fue posible recolectar muestras de perezosos en todo el país. Nuestros resultados sólo reflejan las áreas en las que pudimos enfocar nuestros esfuerzos de muestreo.

1) Los perezosos del área Norte son genéticamente distintivos.

Se encontró que los perezosos en el grupo ‘Norte’ eran genéticamente muy distintos en comparación con las otras poblaciones. Esto significa que los perezosos en esta región son sustancialmente diferentes de los perezosos en otras áreas de Costa Rica que muestreamos. Sugerimos que reconocer a esta subpoblación como una unidad separada puede ser importante para fines de manejo y conservación.

Una subpoblación distintiva como esta podría considerarse una Unidad Evolutiva Significativa.


Gráfico tomado de la publicación original. En el mismo se aprecian los puntos de muestreo.

2) Los perezosos en áreas altamente urbanizadas presentan endogamia.

Los perezosos en el grupo ‘Oeste’ tienen niveles más altos de endogamia (cuando individuos que están estrechamente relacionados se reproducen). Esto puede no ser sorprendente si consideramos que los perezosos aquí están restringidos a vivir en parches de bosque severamente fragmentados dentro de la región altamente urbanizada de San José.

Esto sugiere que debemos centrar más esfuerzos de conservación e investigación en esta región para comprender mejor los efectos a largo plazo de la fragmentación del hábitat.

sloth genetic deformities

3) Los perezosos han sido translocados por humanos.

Finalmente, y quizás lo más importante, descubrimos que la genética de los perezosos en los grupos del Oeste, Este y Sudeste eran sorprendentemente similares. Esta estrecha relación entre los perezosos que viven en lados opuestos de Costa Rica es un resultado inesperado y potencialmente preocupante. Particularmente si tenemos en cuenta la gran distancia geográfica entre estas poblaciones y la incapacidad de los perezosos para trasladarse largas distancias.

Curiosamente, se descubrió que las poblaciones de perezosos en el Caribe Sur eran más genéticamente diversas y tenían altos niveles de mezcla (lo que significa que muchos perezosos de muchos orígenes diferentes se han estado reproduciendo entre sí).

Todo esto apunta hacia la translocación geográfica de los perezosos por parte de los humanos en Costa Rica, donde los individuos han sido retirados de sus áreas de origen y liberados en otro lugar.

genetica de perezosos costa rica

¿Cómo pudo pasar esto?

Cuando consideramos que aproximadamente 3 -4 perezosos son admitidos en centros de rescate todos los días en el Caribe Sur, no es sorprendente que algunos de estos animales puedan haberse originado desde más lejos.

La translocación de la vida silvestre fue particularmente frecuente en los años anteriores cuando no había tantos centros de rescate que supieran cómo cuidar adecuadamente a los perezosos. El gobierno de Costa Rica solía entregar regularmente perezosos de todo el país al Santuario de Perezosos en la costa del Caribe, ya que se los consideraba los únicos expertos en rehabilitación de perezosos en aquel momento.

Esto ha cambiado desde entonces. En la última década ha habido una explosión de nuevos centros de rescate. Costa Rica ahora tiene más centros de rescate por kilómetro cuadrado que cualquier otro país, con más de 250 instalaciones registradas que actualmente rescatan y rehabilitan la vida silvestre. La abundancia actual de centros de rescate significa que la translocación de perezosos a través del país puede ser un problema menor, pero la regulación de los protocolos de liberación es más difícil.

¿Es esta mezcla genética algo malo?

No lo sabemos, pero podría serlo.

Generalmente, los altos niveles de diversidad genética se consideran algo bueno en la conservación de la vida silvestre. El aumento de la diversidad genética significa que se ha producido menos endogamia y esto brinda a las poblaciones una mayor capacidad de adaptación ante el cambio.

Sin embargo, como con la mayoría de las cosas, rara vez es así de simple. Mezclar individuos de diferentes orígenes genéticos también puede tener un efecto peligroso sobre la salud y la viabilidad de las poblaciones a través de un proceso llamado “depresión exógena”.



Los animales a menudo tienen adaptaciones genéticas únicas que los ayudan a sobrevivir en el entorno particular en el que viven. Por ejemplo, los perezosos que viven en regiones montañosas tienen adaptaciones para hacer frente a un clima más frío, que incluye un pelaje más largo, más grueso y más oscuro en comparación con sus contrapartes de las tierras bajas. Al mover individuos de un lugar a otro, estas adaptaciones pueden perderse y el entrecruzamiento puede afectar negativamente la salud de estas poblaciones.

Esta situación se descubrió recientemente en los orangutanes que fueron reintroducidos en la naturaleza desde instalaciones de rescate en Borneo sin conocimiento sobre los antecedentes genéticos y el estado de las subespecies de los individuos.

En línea con esto, existe una conciencia global emergente de la necesidad de considerar los genotipos de los animales antes de la liberación, incluidas las directrices y recomendaciones oficiales establecidas por la Unión Internacional para la Conservación de la Naturaleza. Sin embargo, en Costa Rica, actualmente no existen protocolos o leyes existentes para alentar o regular esta práctica.

Los perezosos de las tierras bajas tiene características diferentes a los perezosos de su misma especie que habitan las zonas montañosas./ Photos: Suzi Eszterhas


¿Qué significa todo esto para la conservación de los perezosos?

La diversidad genética de las poblaciones separadas de perezosos ha surgido en el transcurso de millones de años. Al mezclar poblaciones que tal vez no han estado en contacto durante milenios, podríamos estar causando cambios irreparables que se perpetuarán por generaciones.

Puede ser que los diferentes orígenes genéticos de estas poblaciones no tengan efectos negativos en absoluto. Pero ¿y si lo hacen? En tal caso, habremos comprometido inadvertidamente la viabilidad de las poblaciones de perezosos salvajes. Llegado a ese punto ningún esfuerzo de conservación podrá revertir ese daño.

¿Vale la pena el riesgo?


Este descubrimiento implica que los centros de rescate en Costa Rica deberían considerar el trasfondo genético de los perezosos rehabilitados al planificar futuras reintroducciones. Los perezosos deben ser liberados en su área de origen siempre que sea posible.

Sin duda, esto presentará un gran desafío para los ya sobrecargados centros de rescate con fondos insuficientes. Combinado con una presión cada vez mayor de monitoreo posterior a las liberaciones, parece imposible que los animales regresen a su lugar de origen y además se les rastree para garantizar su supervivencia.

Además, puede que no sea siempre posible devolver siempre un animal al lugar de donde vino. Puede haber una falta de hábitat adecuado en esa área, o el centro de rescate puede no tener registros precisos de dónde se encontró originalmente al animal. Esto se debe a que los animales rescatados a menudo pasan por varias manos antes de llegar a una instalación de rescate, y rastrear el origen del individuo a veces puede ser difícil.


Entonces, ¿qué podemos hacer?

No existe una solución fácil, pero debemos trabajar juntos para encontrar una.

En última instancia, se requerirá una mayor asistencia y financiación gubernamental. También será necesaria la colaboración entre diferentes centros de rescate y sitios de liberación en todo Costa Rica. Se requerirá una mayor transparencia y un mejor registro para garantizar que los perezosos rescatados sean devueltos a donde fueron encontrados.

Además, es menester la preservación del hábitat donde viven estas poblaciones distintivas de perezosos, ya que no se deberían liberar en otro lugar.

Cuando los perezosos eran transportados por todo el país, no sabíamos las consecuencias que esto podría traer. Ahora lo sabemos. Equipados con este nuevo conocimiento,  podemos asegurar que nuestras acciones para ayudarlos realmente conducirán a un futuro saludable para las poblaciones de perezosos en Costa Rica.




Endangered Sloths

Endangered Sloths

This week we are celebrating Endangered Species Day by taking a closer look at the two types of sloth that are currently threatened with extinction. There has never been a more important time for conservation action, with a UN report declaring that over 1 million species are now at risk of extinction.

The loss of species and habitats now poses as much danger to life on Earth as climate change does.

While this news is shocking, we still have good reason to be optimistic. Every single person has the power to save endangered species. The way that each of us shops, eats, and the small choices that we make in our everyday lives all influence the likelihood of many species surviving. Please don’t ever underestimate the collective impact of your daily actions!

Of the six species of sloth that exist today, two are threatened with extinction.

1. The Maned Sloth

The maned sloth is a bit of an oddball – a species of three-fingered sloth which boasts a mane like a lion! These elusive creatures (which look remarkably like a coconut with a mullet) now only exist in a tiny strip of Atlantic forest on the coast of Brazil and are currently listed as vulnerable due to habitat loss.

There is also some evidence to show poaching for both food and the pet trade are contributing to the problem. The maned sloths are larger and more aggressive than the other species of three-fingered sloth, and they are the only species in which males do not develop a brightly coloured “speculum” (an orange patch of fur on the back) at sexual maturity!

Maned sloth


2. The Pygmy Sloth

The second endangered species on our list is the pygmy sloths. These are the smallest (and cutest?) species of three-fingered sloth and can only be found on a remote, uninhabited island off the coast of Panama. They were only identified as a new species in 2001 and are most famously known for their swimming abilities.

They are thought to be approximately 40% smaller than their mainland counterparts and although the population size remains unknown, these little sloths are considered to be one of the most critically endangered mammals in the world. They average around 3 Kg in weight and are approximately 24 inches long, looking very similar to the brown-throated sloth.

Pygmy sloth


If you would like to know what YOU can do to help save sloths from extinction, we have compiled a list of 7 simple ways that you can help sloths today!

If you would like to make a gift to support our work during these uncertain times, any contribution is greatly appreciated. Donations, symbolic sloth adoptions and merchandise purchases all help us in our mission to protect sloths.

Anteaters: The Sloth’s Closest Relative!

Anteaters: The Sloth’s Closest Relative!

The Xenarthra family

What exactly is a sloth? Are they related to bears? Monkeys? Marsupials? No! Sloths are actually part of a super ancient (and super strange) family of mammals called the xenarthrans (pronounced zen-ar-thrans). In fact, it is thought that this family is one of the oldest groups of mammals left alive today and it includes our beloved sloths as well as anteaters and armadillos. The very name ‘xenarthrans’ literally translates in Greek as “strange joints” and it’s members all share unique articulations in the lower spine.


Xenarthra filogenetic

Among the most famous and ancient of all xenarthrans is probably the Megatherium – an extinct type of Giant Ground Sloth that grew to over 25 feet tall! The first fossils of this animal were originally found by Charles Darwin near Patagonia, Argentina. Did you know that these giant sloths are the reason why we have avocados today? We will dive into the xenarthran family history in more detail in a future post, but for today we want to focus on the sloths closest relative: the anteaters!


What is an Anteater?

The obvious definition would be an animal that eats ants (and termites) – but this would actually apply to all kinds of unrelated animals (such as the aardvarknumbatechidna and pangolin)

Aadvark equidna pangolin
Long snouts are useful for insect eaters!

Scientists originally thought that these different species of ant-eating animals were all directly related because of their similarities: the diet, long tongues, very few teeth, powerful forearms, and tube-like snouts. However, we now know that these species developed their matching features through a fascinating phenomenon called “convergent evolution”.

Convergent evolution is a process where two very different species develop similar traits. The two types of sloth that we see today are also fantastic examples of this – they separated off from each other approximately 30 million years ago and acquired their upside down arboreal lives independently.


Anteater Anatomy

Before we talk about the different types of anteater (yes, there are 4 very different species), lets take a moment to appreciate how wonderfully weird these animals are.

Just look at that face!

Eating insects can be complicated. If you have ever accidentally disturbed an ants nest you will know how unpleasant they can be when aggravated! To avoid this painful situation, an anteater has to act quickly. Thankfully they have ridiculous tongues which makes the whole process much easier. The tongue of an anteater starts at the breastbone and can extend up to two feet long. It is also covered in backward-facing spines and super-sticky saliva for maximum insect collection.

An anteater will break open a nest with it’s powerful sloth-like claws, and then use its long, sticky tongue to lap up as many insects as possible within 60 seconds. They will extend their tongue up to 150 times per minute and can eat up to 30,000 insects per day with this method!

It takes the ants a few moments to realize what is happening, and so by the time they mount a counter attack, the anteater is ready to move on. By only feeding from each nest for a few seconds, the anteater doesn’t completely destroy the colony and so they can always go back for more in the future. The ultimate sustainable diet!



The anteater’s long snout is actually an elongated jaw and they have no teeth at all! Well, they don’t really need them for a diet of ants and termites. They also have poor eyesight – they detect insects with their powerful sense of smell which is up to 40 times that of a human! Poor eyesight and a fantastic sense of smell is a feature shared with the sloths!

When threatened, anteaters will stand on their back feet and open their arms to look bigger. Giant anteaters have been responsible for at least three human deaths, and in all three cases the anteater had been provoked. There’s a lesson to be learned here – don’t poke an angry anteater.


anteater standind meme
You don’t want to pick a fight with an anteater!

The Four Species of Anteaters

1. Giant Anteater (Myrmecophaga tridactyla)

giant anteaters
Giant anteaters, as the name suggests, are the world’s biggest anteater species


Giant is no exaggeration. These guys are the biggest of the family and can reach up to 2 meters (7 ft) in length and weigh up to 50 kg (110 lbs). They are mostly terrestrial and diurnal, and can be found in multiple habitats throughout Central and South America, such as rainforest, grasslands, and savannas.



The scientific name means “ant eater” and “three fingers”, but these animals actually have five digits on the end of each limb (just like the sloths, early explorers apparently couldn’t get the number of fingers/toes right). Because the claws on their front limbs are so large, giant anteaters have to walk on their knuckles (in a similar way to gorillas).


Like sloths, the body temperature of these animals is very low in comparison with other mammals, and their main predators are big cats like jaguars and pumas. Thankfully, however, the giant anteaters are slightly better at defending themselves than a sloth!

This species is listed as Vulnerable by the IUCN as the population is declining. The biggest threats include habitat loss, poaching, wildfires, and road traffic collisions.

2. Silky Anteater (Cyclopes didactylus)

sliky anteaters
Smallest of the four anteater species, the silky anteater, lives in the treetops of south and Central America.


These golden hamster-sized anteaters have to be seen to be believed. Also known as ‘pygmy anteaters’, they measure just 18 inches long from nose to tail and weigh less than 1 lb (400 g). They are the least studied of all the anteaters, probably because they are not only small but also nocturnal and arboreal! Trying to locate a fluffy golden tennis ball at the top of a huge rainforest tree is no easy task – particularly when their favourite tree (the ceiba tree) produces fluffy golden seed pods that look suspiciously like silky anteaters.

Two years ago scientists discovered that there are actually 7 different silky anteater sub-species, although they suspect this might just be the tip of the anteater iceberg. Scientists really don’t know anything about these strange little animals – including how many of them are left in the wild. They are officially listed as “Least Concern” by the IUCN, although the true population status of the 7 subspecies is unknown.



3 & 4. Southern Tamandua (Tamandua tridactyla) and Northern Tamandua (Tamandua mexicana)

Tamandua is a genus of anteaters with two species: the southern tamandua and the northern tamandua.

The last two species are also known as the lesser anteaters (which feels like a slightly insulting name). Both are similar in shape, color, and size: an average length (including tail) of 130 cm and weighing up to 5.5 kg (similar to a fully grown sloth). On the spectrum of anteaters, these guys fall somewhere in the middle between the giant anteater and the tiny silky anteater.

Just like the giant, they have long claws on the front feet that make walking difficult, but like the silky they are also adapted to live, sleep and forage in the canopy of trees. You might wonder how an animal that eats ants finds any food in the trees. Thankfully, these tamanduas also have an appetite for termites, and termites like to build their nests at the tops of trees. The tamanduas strong, prehensile tail provides them with a safety rope while clambering around at the top of the rainforest looking for termites.

As the names suggest, the Southern Tamandua lives in the rainforests of South America, while the Northern Tamandua is found up North in the rainforests of Central America. Both species are listed as “least concern” by the IUCN.


Are anteaters good pets?

Before you ask: no! You should not have one as a pet. These are wild animals that do not enjoy human contact. The giant anteater and the tamanduas can defend themselves perfectly well with those big claws, but the silky is more vulnerable. We know they are wonderfully weird and admittedly very cute, but they need to live in the wild. Even if you found one and took it home, it wouldn’t survive more than a few days in captivity (and then you’d feel pretty horrible).

Most of the anteaters (and sloths) that are sold as pets come from the illegal wildlife trade. This means that poachers in South and Central America have killed a mother to retrieve a baby that is easier to trade.

If you want to get some anteater action (highly recommended), you can always go to see them at a reputable zoo, conservation center or wildlife rescue facility (check out our guide for ethical animal encounters at zoos to make sure you aren’t accidentally supporting animal exploitation). If you get lucky, you might even see one in the wild if you plan a trip to Central or South America!






Know your Sloth Predators: The Great Harpy Eagle

Know your Sloth Predators: The Great Harpy Eagle

The Harpy Eagle holds the crown as the most powerful eagle in the world – and it also happens to be the sloth’s main predator! With talons larger than a grizzly bear and a grip strong enough to crush a human arm, you can see why sloths take camouflage so seriously. Here we explore the terrifying world of the Harpy Eagle and explain how protecting sloths also means protecting these magnificent birds!

A living myth

Have you heard of the harpies of Greek mythology? A harpy is a mythological creature that was depicted as a fearful, winged beast with the head of a woman. Known for their cruelty and destructive nature, they were nicknamed, the “Hounds of Zeus.”

Photos: First photo, Second photo: kabeza

It’s not surprising that in some areas of Latin America, stories and local legends still exist about witches living in the tops of tall trees. For those few fortunate enough to see a harpy eagle in person, they do look like the silhouette of a robed person sitting on a branch.

harpy eagle
Photo: leon_moore_nature_experience

Claws as big as a grizzly bear’s

Unlike the harpies of Greek mythology, harpy eagles (Harpia harpyja) are very real and rank among the largest birds in the world. They can weigh up to 11 pounds/5 kilograms and females are often twice the size of their mates. They are also some of the most powerful birds: with the ability to lift prey the size of monkeys, sloths or even a baby deer!

These massive birds of prey can be 3.5ft/1m tall and have an impressive wingspan of 6.5ft/2 meters! Unlike other raptors, they rarely soar through canopy of the rainforest and instead prefer to move from tree to tree.

With a grip strength up to 10x higher than humans: 13cm of pure raptor power. / Photo: DecorahPagent

It’s dinner time!

Harpy eagles don’t hunt every day because they can feed on the same kill for several days in a row. Their bodies have adapted to tolerate meat that has spent several days in the hot environment of the tropical forest. Because they don’t need to eat every day, they can actually spend an entire week or more without ingesting any food!

Although Harpies prefer tree-dwelling animals, such as sloths, monkeys, iguanas, and other birds, they can also prey on ground dwellings species such as coatis, large rodents, deer or wild pigs.

harpy eagle sloth
A harpy eagle catching a sloth. @LaSalle museum of natural sciences, Costa Rica

They make great parents

Harpy eagles reach adulthood when they are about 5 years old. Like a lot of species of birds, they mate for life, which, for a harpy eagle, could mean 25 to 30 years! Once an individual finds a partner, it’s time to build a nest in one of the tallest trees of the forest.

Both parents participate in the building of the nest, which is 6ft/2m in diameter and more than 1ft/40 cm deep. Two adult humans could easily fit in the nest! The female lays two eggs, however, usually only one of the chicks survive. The parents look after their offspring for the first two years until they become a juvenile.

The relationship between sloths and harpy eagles

Harpy Eagles are what scientists, biologists, and zoologists call an “umbrella species“. Just like several people are protected by one umbrella under the rain, different species of wildlife can also be protected by conserving one particular species.

Harpy eagles depend upon on a healthy population of monkeys and sloths. So to safeguard the future of this raptor we must protect these species. By protecting harpy eagles, we conserve the amazing rainforest in which they live, which is also the home of sloths, monkeys and many more incredible creatures.

Conservation status

Unfortunately, according to IUCN Red List, the population of harpy eagles is declining all over the continent.  It’s hard to accurately determine their population numbers – some estimate that there are between 10,000 to 50,000 individuals remaining, although the data is still insufficient. In some countries, the species is considered extinct. The Harpy Eagle is near threatened or vulnerable in most areas of South America, and critically endangered in Central America.

harpy eagle home range
Home range of harpy eagle

Big predators usually require large territories to provide all of their needs: hunting, mating, etc. Habitat loss, logging, and the effects of the climate crisis are undoubtedly the biggest threats to harpy eagles. Trophy hunting, poaching, and trafficking for the illegal pet trade are also big issues. Some people kill them because they fear that the harpy eagle could hurt them, their children or their livestock. As mentioned earlier, there are a lot of misconceptions and mysticism surrounding these raptors.

However not all hope is lost: several organizations across the continent are working hard to conserve and protect harpy eagles. The Peregrine Fund has a fantastic project that breeds harpy eagles in captivity and releases them into the wild in Panama. You can also read this great article about the experiences of PhD Eduardo Alvarez Cordero in Venezuela – one of the first people to study harpy eagles.

harpy eagle
Photo: Jitze Couperus

A witch of the rainforest, a mythological creature, an inspiration for movie characters. Harpy eagles not only capture our imaginations, but are indispensable to the health of our tropical ecosystems.

Thunderbird from Fantastic Beasts and Where to Find Them, Photo: Gavin

-Cecilia Pamich