The Urban Sloth Project Recap – Part I (November 2020 to December 2021)

The Urban Sloth Project Recap – Part I (November 2020 to December 2021)


In the South Caribbean of Costa Rica, it is pretty common to find sloths in unusual places: on a restaurant cutlery shelf, a hotel ladder, a fruit stand, clinging to a truck… you name it, sloths have been there. World-renowned wildlife photographer Suzi Eszterhas came to the South Caribbean to take eye-opening photographs of the lives of these sloths in urbanized areas.


sloth between two buildings


The Urban Sloth Project

The Urban Sloth Project aims to study how habitat loss and disturbance in the form of urbanization affect the lives of sloths. How often must they come to the ground to change trees, rather than use canopy branches? How long does it take them to traverse the ground? Are they resting lower down than their counterparts living in optimal rainforest conditions?

If so, is this a behavioral factor, or are they forced lower because the trees are not as tall and mature? Must they change trees more frequently to find suitable leaves? And how much variation is there in their diet?


sloth on a powerline


These are just some of the questions we are aiming to answer through the Urban Sloth Project!

We had our USP timeline mapped out, but unexpected pitfalls, as well as some exciting opportunities, have meant that the old saying has proven itself true, once again – the best-laid plans of sloths and scientists go oft awry.

We would like to share our stories and experiences from the first year of the Urban Sloth Project: the sloths, the trackers, the tears, and the joy.



First came Sharon 

Sharon was a small juvenile two-fingered sloth (Choloepus hoffmanni), and our very first Urban Sloth. We found her while out scouting for our first urban sloth, she was being harassed by dogs while trying to make her way to a Beach Almond tree (Terminalia catappa). Luckily, our team was there to keep her safe.  She helped us as we got our tracking legs underneath us and figured out how the USP was going to work!


sharon urban sloth
Sharon is the first sloth collared for the Urban Sloth Project. She was rescued on the side of a road while being harassed by a dog.



Then came the Bradypus

Next, we collared the first of our three-fingered sloths (Bradypus variegatus): Alan, from the beautifully connected eco-hotel Kukula Lodge, and Croissant, whose original territory covered a road undergoing a huge amount of deforestation and construction.


sloths recap

Backpacks for everyone! 

Our next Urban Sloths were Cacao and Laurel: both Choloepus and both named after the trees they were found in, and made SloCo history as the first subjects for our famous sloths’ backpacks.

(The sloth backpacks, also called Daily Dairies, track millions of data points every minute as sloths move about the canopy; measuring when they climb, descend, stay still, how fast they move while doing so, and many other activities never before measured in wild sloths.)

Cacao’s territory was an aesthetically beautiful, well-manicured garden that unfortunately didn’t have much connectivity between the trees, forcing Cacao to cross on the ground every time he needed to change trees.


cacao sloth
Cacao, found in a cacao tree!


Laurel, meanwhile, took his backpack and disappeared onto private property inaccessible to the Tracking Team, where he stayed for nearly two months. The mature and well-connected property was full of tall Laurel de la India, also called Weeping Fig (Ficus benjamina), with one goliath Sandbox tree (Hura crepitans) in the center. This, as well as the abundance of other sloths in the area, made tracking Laurel difficult.




The Tracking Team was therefore very excited when he returned to his original spot, and with some carefully placed feet on shoulders and a pair of scissors, we retrieved his backpack and un-volunteered him from the USP.


MARCH 2021

The first fatality 

In March we got a call from a local rescue center that Cacao had been admitted after being attacked by dogs. He survived his initial injuries, but did not survive the resulting secondary infections, and passed away in April, a month after the attack.

Luna and Sol 

Although we had lost our beloved Cacao, we were able to collar Luna and her baby Sol, who would go on to become some of our favorite sloths of the USP. A spontaneous addition to the project, Luna was crossing the main road of Puerto Viejo when she was found by Dr. Cliffe.

Sol was our very first baby of the project, and we were privileged enough to watch him grow and eventually gain his independence from Luna!



Houdini the Sloth, aka Sharon

Our first USP mystery – Sharon found her way out of her collar. This was unprecedented in sloth tracking, and we still have many questions that will likely never be answered.



Finding the intact collar on the ground caused great concern that Sharon had been attacked, and the worst-case scenario was that she was nearby, but injured and in pain. Our trackers searched for her, however, five days later she turned up in one of her favorite spots, sans collar, but totally unharmed.


APRIL 2021

Hello to our highest friend

Arthur--a regal adult three-fingered male living between a yoga retreat and some luxury rentals–joins the Urban Sloths as the first three-fingered sloth with a backpack, only to have them disappear high into some dense and well-connected canopy.


VIP subscription
Arthur the handsome.


MAY 2021


Only a few months after relieving Laurel of his backpack, we were informed of a huge amount of deforestation in Laurel’s area. Devastatingly, Laurel’s entire territory, as well as many other trees along the road, had been cut down.


deforestation habitat loss
Dr. Rebecca Cliffe is next to what used to be Laurel’s trees. Photo: Suzi Eszterhas


When Team Sloth went to investigate the damage, there were displaced sloths everywhere we looked. We were able to relocate some to more appropriate areas, and we could only hope that Laurel himself survived the destruction.


man walking a dog next to a sloth
This sloth and her baby were displaced sloths. With no trees, she remained in the hibiscus bush, exposed to dangers, like free-roaming dogs. Photo: Suzi Eszterhas.

These problems are a direct result of the exact issues we aim to address in the USP, and in spite of the heartbreak from witnessing this kind of deforestation, Team Sloth is more determined than ever to gather this important data on sloth behavior and ecology in urban environments-our ability to scientifically document these events is the only way to effect change.

Hello mango! 

Wildlife photographer Suzi Ezsterhas visited SloCo to document the plight of Urban Sloths. While searching for sloths to photograph, Team Sloth stumbled upon a small, wet ball of fur among fallen leaves and coconut husks along the beach path directly opposite SlotHQ. We bought the little three-fingered sloth in from the cold, where she huddled up to Jim, SloCo’s mascot, and promptly fell asleep.


baby sloth cute with teddy bear
Mango became a favorite instantly!

After dining out on some fresh baby guarumo leaves (Cecropia sp.) from our tree nursery, we took the opportunity to fit baby Mango with a tracking collar.

Next to Croissant… Baguette!

We came across a female three-fingered sloth clinging to the top of a fence: she was trying to escape a pack of barking dogs protecting their territory. Team Sloth fought through the pouring rain to rescue the sloth, but before releasing her we fit her with a collar and named her Baguette, since she was found on the same bakery road as little Croissant.


VIP adoption

We’d like the Nachos, please!

Welcome Nacho, one of the most remarkable sloths of the USP! Nacho was first fitted with his collar at a cantina on Cocles beach, and named after Team Sloth’s favorite dish there. Over the next couple of weeks, Nacho made his epic journey all the way from Cocles to downtown Puerto Viejo.



The Tracking Team followed him on his journey to some rather strange places for a sloth to hang out: isolated beach almond trees on the side of the road, the middle of a lively bar, and a restaurant … We soon began to refer to Nacho as out party sloth, for his proximity to human activities.

JUNE 2022

The second fatality

As we were waiting for an opportunity to recollar, we were faced with the second fatality of the USP in June of 2021. Sharon had been electrocuted while using an uninsulated powerline to move between trees.

We were devastated by Sharon’s death and vowed to renew our efforts to understand and help sloths adapt to human-impacted environments.


Farewell, Sharon

The traveler sloth

Nacho surprised us all by traveling over two kilometers in two weeks, a feat we had not previously known was possible for a sloth.

JULY 2021:

We recaught Mango to swap his backpack for a collar. Since he was so young and small when we first fitted him, we knew we’d have to check him often to make sure he didn’t outgrow it. We were pleased to find that he was healthy and growing just as expected.



Croissant’s big move

Throughout late August 2021, we were having a lot of trouble tracking Croissant. The inconsistent signals from her VHF collar were proving difficult for our tracking team to triangulate.



It turns out that she had crossed a lengthy deforested gap by traversing fences and roads to an undeveloped piece of land near the center of town, around 500m away. Since her territory was in the process of undergoing a large amount of deforestation and disturbance, it makes sense that she would seek out greener pastures.

While this area is much more difficult for our team to track her in, it is a much more appropriate sloth habitat, and she has remained there ever since.

Nacho’s intervention

Nacho made it all the way to town this month and took shelter in a restaurant during a rainstorm. While it isn’t too unusual for urban sloths to wander into the local eateries, Nacho decided to climb around under the tables and try to bite the customer’s ankles.



Since this is bad for business, the restaurant owner called the local rescue center, who removed Nacho and called us. After a health check and monitoring period, Nacho was found to be fit and healthy, so we took the opportunity to swap his collar for a backpack!



He was then released into one of the only appropriate habitat spots in his home range; the dreaded swamp which Croissant had also moved to. Over the next few days Nacho crossed the street to one of Puerto Viejo’s liveliest beach bars. There were a few well-connected trees on the property, and Nacho seemed unconcerned by the constant stream of patrons and loud music.


Croissant health check

First collared as a young adult, we had some concerns that Croissant might eventually outgrow her collar. She had been difficult to find in her new home territory, but at the first opportunity, we gave her a health check and tech adjustment. We were pleased to find that although she had grown, her collar had not become too tight and still fit her well. Finding no adverse physiological effects of the tracking equipment was vital to the continuation of the USP!



The case of the missing tracking equipment / Bye. bye Nacho

Underneath Nacho’s favorite trees is the permanent camping spot of a man who is not our biggest fan, and took it upon himself to remove Nacho’s tech. He seemed unaware or uncaring that we knew he had Nacho’s backpack, and when we found and refitted Nacho with a collar, he removed that too.


Behind these palms was Nacho’s tech.

Team Sloth made the difficult decision to not recollar Nacho. We really liked having him in the USP, but we could not risk his well-being by making him a target for people who would handle him and steal our expensive equipment, and so we removed him from the project.



Good luck Sol!

During the month of October, the Tracking Team had noticed baby Sol going through his rebellious teenager phase: he wanted to be further away from his mum and venture out on his own. It started with three limbs rather than four clinging onto Luna’s fur, a set of claws gripping onto a vine instead. Then Sol was seen next to Luna, rather than on her. Then one day, he wasn’t with her at all! Luna gifted Sol a portion of her territory and little Sol was officially all grown up.


Luna without Sol

Always high in the canopy

Baguette remains our most difficult sloth to monitor, and we finally got a chance to retrieve Arthur’s backpack, allowing us to download millions of data points from the backpack (which are still being processed by specialized computers in the Swansea University lab) and confirm that the backpack design works great.


Arthur with his new collar.



The case of the missing collar

One Friday while out tracking, we were receiving no signal at all from little Mango’s collar. While it was possible Mango had decided to move further afield, she would have had to have moved over 10km in less than 24hrs for the VHF signal to not reach the receiver! We know sloths can move faster than most people give them credit for, however this was very much beyond Mango’s capabilities.



We believe that as Mango’s favorite spots were low down, and often in plain sight if you knew where to look, someone walking along the beach saw little Mango and his little collar, and didn’t know what it was. Luckily, the next day some members of Team Sloth were enjoying a weekend at the beach when they noticed Mango sitting low on her favorite guarumo trunk and she was recollared with little fuss! Mango responded to this collar-napping by venturing across the beach path, and she has since doubled the size of her old territory.


Just before Christmas, Luna’s territory was being deforested, leaving a dozen sloths and countless other wildlife homeless. However, the community was not going to stand for this. Community members and local organizations, including SloCo, were able to temporarily halt the work and contact the authorities, who had the power to permanently stop the intended development.



Stay tuned for Part II !



If you would like to receive real-time, monthly updates from the Urban Sloth Project, featuring updates on all of our Urban Sloths, plus biographies, illustrations, and other exclusive materials, you can sign up for our VIP program!


International Women’s Day

International Women’s Day

March 8th is International Women’s Day, when the world takes a moment to step back and commemorate the achievements, and activism of women. 

Well-behaved women rarely make history. –Laurel Thatcher Ulrich


Biography | Laurel Thatcher Ulrich


Too much of history has centered around erasing, denying, or minimizing the contributions of people who make up slightly more than half of the human race, and acting as if their achievements are some kind of aberration or new fad. They are not.

It takes courage to speak the truth and change the way the world works, but only by doing so can we build a better future. So, here’s to the women who “misbehaved” to make the world a better place—Cheers to that! 

Some days I am more wolf than woman, and I am still learning how to stop apologizing for my wild. –Nikita Gill


We here at SloCo do not believe that the wild, within us or outside of our door, is anything to apologize for. Nature has made each of us what we are: tree, sloth, wolf, or woman, we have each been optimized by three and a half billion years of evolution to be something unique, something amazing, and a part of the wilderness that is our origin and our home.

We don’t save the forests because they are a nice place to have on the other side of a window, but because they are a part of our hearts, minds, and spirit. So, here’s to the wild women—Cheers to that! 

Surround yourself with people who are going to lift you higher. –Oprah Winfrey

Oprah Winfrey
Photograph: Kevin Mazur/Getty Images for Robin Hood

The best part of working in conservation is the awesome people you work with. There is nothing better than working WITH others, cooperatively rather than competitively, towards a shared passion and goal. SloCo was founded by a woman and has retained many women in strong leadership roles in order to lead by example that achievement is not a zero-sum game.

This attitude is what makes SloCo’s community-based conservation initiatives so successful and so sustainable. So, here’s to the women who win, and who share their victories with others—Cheers to that!


There is a moment where you have to choose whether to be silent or to stand up. –Malala Yousafzai


Malala Yousafzai y su lucha por el derecho a la educación


Sloths do not have voices—we must speak for them. The forest has no language—unless we learn to listen. When people and places are threatened with “development” that leaves no room for nature or diversity, no room for animals, individuals, or cultures to call home, it can feel very lonely.

When people stand up for what they believe in, not just for themselves but for others, we will find that the truth has a profound power to change the world for the better. So, here’s to the women who will not go quietly—Cheers to that!


How wonderful it is that nobody needs to wait a single moment before starting to improve the world. –Anne frank


Anne Frank - Biquipedia, a enciclopedia libre


The goals of social and environmental justice are long and far-reaching, but just because they are ambitious does not mean they are unachievable!

The future is not something you wait for, it is something you work for, and we are here to work for it, every single day. So here’s to the women who set the future in motion—Cheers to that!

-Ames Reeder

All sexes, genders, colors and, species. Tracking Diaries #1

All sexes, genders, colors, and species. Tracking Diaries #1

“Oh my gosh,” says my boss, holding the binoculars to her face. “I think Croissant is a boy.”

I take my eyes off the beeping box attached to our portable radio antenna and peer into the trees, trying to find the small, tan-colored sloth amongst the palm fronts and tree bark. Boy or girl, I personally think Croissant might actually be a coconut, but I defer to Amelia’s experience.

I also sympathize; it took me 27 years to figure out that I, too, was mislabeled as a girl, and longer than that to correct it. Luckily for the alleged sloth, or possibly coconut, SloCo is a very friendly and open organization and we can easily update our records. We also do not discriminate: both people and sloths of all sexes, genders, colors, and species are welcome here.

Croissant is one of our Urban Sloths; sloths who have been volunteered to wear temporary radio collars and be studied so that we can better understand sloth behavior and how it is affected by humans in their environment. To this end we go out every day and track down each sloth, trekking through dirt roads, abandoned lots, overgrown jungle, and occasionally backyards to find our Urban Sloths and gather data. I pull out a device for triangulating the height of trees and begin taking measurements of Croissant’s height, the tree that she (or maybe he) is in, and any observed differences since they were last spotted. As I do so, the radio antenna on my back shifts, pointing away and begins beeping louder.

“Amelia?” I ask. “Are we sure that’s even Croissant?”

“It must be! How many tiny, 3-fingered sloths sleep in exactly this position, in exactly this Sangrillo tree, and also look exactly like Croissant?”

“Only, according to the radio, the sloth we’re tracking is over there.” I point in the opposite direction of where we are looking. “Do we have a confirmation of the collar?”

Amelia puts the binoculars up to her face again. “Not yet,” she grumbles, and soon we are climbing over the truck, standing in mud puddles (this would be me), craning our necks and using cell phones as zoom lenses to see if the alleged Croissant is wearing a radio collar. After a while, exhausted, hot, and covered in mud (mostly me), we have to admit that we cannot confirm this is our sloth. If sloths were people, we could just ask: Excuse me, what is your name? What are your pronouns? Do you like this tree? By the way, do you mind wearing a radio collar for a few months?

We spent the rest of the afternoon looking for the real Croissant, who, according to our instruments, is either 30 meters in the canopy pretending to be a termite nest, has buried her collar in the ditch, or has invented a new form of teleportation as a defense mechanism against being tracked.

Eventually, it begins to rain.

I run the equipment back to the truck while Amelia updates our records for the last several days with our new uncertainties. We don’t always like uncertainty, but this is science: just because something is easy doesn’t mean it is right, and making assumptions is not how you learn the truth.

Tomorrow we’ll be back again, looking not for the truths we want to impose upon others, but for the ones they have to teach us, if we are willing to listen.





Urban Sloth Project Volunteer

Do Sloths drink water?

Do Sloths drink water?

You have probably never seen a sloth drinking water. In fact, very few people have! As a result, it has been assumed for centuries that sloths get all of the water they need from the fresh rainforest leaves that they eat, and few documented observations exist of either of the two sloth genera drinking in the wild.

We photographed a male brown‐throated sloth (Bradypus variegatus) lapping water from the surface of a river in Costa Rica. Our latest work ‘Sloths hanging out for a drink’ has just been published in the scientific journal Frontiers in Ecology and the Environment.



This sighting prompts many additional questions. For example, how widespread is drinking behavior and how frequently does it occur? Methods used to assess water retention in wild sloths suggest that this behavior seldom occurs, so drinking is likely a method of maintaining osmotic balance when faced with extreme ambient temperatures, low precipitation, or increased consumption of mature (ie drier) leaves.



If freshwater access is indeed important, there are further implications relating to the captive husbandry of sloths in zoos and rescue centers (where they often face drier climes, typically don’t have access to water, and have a very low survival rate), and for conservation, especially after habitat fragmentation, where changes in land use can restrict water access (eg irrigation diverting stable water sources, roads that are difficult for strictly arboreal animals to cross).

Moving forward, the predicted trend toward a hotter, drier climate for Central and South American rainforests may negatively impact the sloths’ potentially delicate water balance, particularly in view of their limited energy budget and inability to travel long distances. If all sloths need a drink from time to time to stay healthy, it’s important to make sure they can get one.


drinking water


-Dr. Rebecca Cliffe