The Urban Sloth Project RECAP Part III (2023)

The Urban Sloth Project RECAP | Part III (2023)

What a year, huh?! Everything happened in 2023 for the Urban Sloth Project (USP)! We upgraded our technology by saying goodbye to our sloth backpacks and embracing collars with Daily Diaries Data Loggers and GPS trackers. We initiated research collaborations with colleagues from Brown University and the University of Costa Rica.

We commenced the second stage of the USP by monitoring three sloths in pristine primary forests. We started analyzing data from the first backpacks, added new sloths, and bid farewell to some beloved ones.

Before delving into events month by month, we invite you to visit the recaps of part 1 (2021) and part 2 (2022) to refresh your memory of past years. And now, let’s examine some numbers.

2023 the numbers

  • 10 total sloths monitored
  • 8 adults
  • 2 babies
  • 7 three-fingered sloths
  • 3 two-fingered sloths
  • 17 pieces of jungle-resistant tech
  • 0 backpacks
  • 16 collars
  • 16 Data loggers
  • 3 antennas used
  • 1 device lost
  • 9 sloth trackers
  • 350 hours of tracking
  • 3,000 data points manually recorded
  • 3,377,777,777 data points collected by the backpack data loggers
  • Read More: Welcome to Sloth Town

January: A Slow Start to the Year

In January, we resumed our work after some short vacations for the holidays and some days off courtesy of mosquitoes and jungle diseases to start a fresh new year.

We monitored Mango, who remained in her same trees despite the disturbance to her habitat, Luna, who changed her trees for those on the other side of the road; Luiza continued taking care of her baby; Pumpkin was seen, but without signs of baby Pie, Arthur kept up in the canopy; Deborah is now healing her eyes, and Zeus keeps being one of the most elusive sloths.


February: the month of love, but José is on his own!

José was tracking alone for a couple of weeks, and this is more difficult for several reasons: the equipment must all be carried and managed by one person (and juggling tracking antennas with binoculars can be very distracting), it’s not as safe, and, of course, the more eyes on the trees to help spot sloths the better. José nonetheless managed to find some interesting moments this month. Read his Tracking Diaries for a first-person perspective!


Deborah finally healed her eyes!

This month, we found Luna surrounded by male sloths, and one day we even found her on the same guarumo tree next to Luiza! Both sloths looked very similar; that day, it was challenging to identify which sloth was which!


March came busy

March has been a great month for the project: We got a new brand of Daily Diary Data Loggers, and we started the habitat surveys. These surveys consist of making 8 squares of 100 m² where we have collected GPS locations of the sloths and studied the trees inside them.

This way, we can understand how the sloths use the resources and why they choose to stay in those areas. Specifically, we did the 8 squares in Mango’s area, which was really hard since we were still perfecting the methodology for it.

Our volunteer Gabriel measuring a tree.

The highlight of the month was that Croissant had a baby! And we added a new sloth to the USP, who will soon become a favorite of the community: Freckle (you can adopt Freckle here!). Freckle was found with burns from electrocutions, and after a few weeks under veterinary care, she was released near Luna and Luiza. Sadly, this month also brought us some bad news: we found Luna with a broken arm.


Meet the adorable Freckle!

April: Luna’s surgery

Thanks to the amazing support of our community, we were able to organize the surgery Luna needed with a specialized orthopedic surgeon who came from San Jose (the capital of Costa Rica). Luna had a platinum plate to fix her arm, and she began the recovery process.



We purchased a big freezer! This might sound odd, but we are using it to freeze feces and hair samples for our collaborations with our colleagues from Brown University and the University of Costa Rica. This month, our volunteer Faith took the pen and wrote her own experiences working with sloths.

Our Ecology Coordinator and sloth scientist, Amelia Symeou, monitored sloths for the Urban Sloth Project for the first years of the project. She is now analyzing the first batch of backpacks’ data at the Swansea Lab for Animal Movement at Swansea University in Wales.


Amelia working at Swansea University, UK.

May oh May!

This month, Luna once again took the spotlight. Her path to recovery was a rollercoaster! A few days after the surgery, we became concerned as Luna showed no signs of using her arm. Fortunately, one of our valued supporters, Kim, a veterinarian from the US, learned about Luna’s condition and immediately came to Costa Rica to closely monitor her progress.


Luna’s recovery was a rollercoaster.

Kim implemented Low-Level Laser Therapy (LLLT) to aid in Luna’s healing. Shortly after the LLLT sessions, Luna began to show signs of movement in her arm, but she began scratching the surgical wound. After a couple of days of antibiotic treatment, Luna’s condition began to improve.

Freckle is on the move: she’s exploring this new territory, and her journey has taken her as far as 1.2 kilometers away from her initial location!


In this image, you can see part of Freckle’s Journey!

June: Team Sloth Goes to La Selva

This month, we made our first trip to La Selva Biological Station, located in Sarapiquí (north of Costa Rica). This facility is a research haven where scientists from around the world study different aspects of biodiversity, thanks to the well-preserved area with diverse forest coverage.

We came here to collar sloths using a new type of collar with integrated GPS, as no one will be here tracking them, and since it is a primary forest, it is more challenging than usual. We managed to collar 2 Bradypus, one male named “George of the Jungle” and one female named “Misty”.


Misty the sloth, has a cloudy eye.


We also bid farewell to the sweet Mango. After many months of monitoring, we witnessed how Mango went from a tiny baby to an adult. Now, it was time to let her go!


Farewell, dear Mango, you’ll always be in our hearts!

July at ‘Sloth City’

We returned to La Selva to collar one more sloth, Selvina, a two-fingered female sloth, and we welcomed a new sloth in Puerto Viejo: Noah, whom we discovered in an area that we called “Sloth City”, a beautiful forest patch with tall trees just across the road from where Luiza and Luna live.


Welcome to the USP Noah!


‘Sloth City’ is a swampy area adorned with towering Sangrillo trees (Pterocarpus officinalis) that resemble a natural forest skyline, hence the name. Sloth City also serves as an ideal training ground for our Scat Detection Dog, Keysha.

This month, we also had one of the saddest moments since we started this project. After several weeks of rehabilitation, Luna seemed to be improving and showing signs of healing, but suddenly, she passed away. It was a heartbreaking moment for us and for our community, to whom we are forever grateful for all the support we received during those days.


We’ll never forget Luna, the wonderful sloth mother, and we’ll always be grateful to see her raising her adorable babies Sol, Celeste, and Eclipse.


August: the rainy month

The rainy season is finally over at the end of the month, but not before some severe storms, fallen trees, road blocks, and power cuts. These weeks have been difficult to work due to the climate conditions: it’s not only uncomfortable but also dangerous.

September: trying new tech

We visited the sloths at La Selva—Misty, George, and Selvina—and attempted to retrieve data from their GPS collars. Among the goodies waiting for us was a state-of-the-art antenna and a PinPoint Commander, which allows us to wirelessly download the GPS points from the collars.

Setting up the Pin Point Commander!

To do this, we simply have to be in the range of the sloth, whom we locate manually using our usual VHF telemetry methods. We no longer need to capture the sloths; we just need to get close enough to them – a true game-changer! We successfully downloaded data from Selvina and George.

Slothtober: Two and a Half Sloths

Slothtober has arrived, bringing along not one, not two, but two and a half new sloth additions to the Urban Sloth Project!


Gandalf was release after we fitted a collar with a Daily Diary Data logger.


We proudly introduce the sagely Gandalf and Dumbledore, both residents of Sloth City, and the adorable baby Nugget, Luiza’s latest little one. We swapped Luiza’s old VHF collar for a brand-new one with a Daily Data Logger.


Baby Nugget is beyond adorable!


On the 15th, we had a total solar eclipse! We had an extreme visitation in the South Caribbean, and every street, road, and beach was overcrowded, making work impossible. So we called it a day and enjoyed the show!

November: Freckle on the spotlight

We finally finished the Home Surveys! (or at least, the first stage of it). Freckle keeps making headlines when showing up at beach bars and restaurants, thrilling all the beachgoers.


Freckle returned from the area neighboring Luiza to hang out above bars and restaurants.


It was during one of those days searching for Freckle by the busy beach when a young and curious man approached us to ask what we were doing. Farhan later became a volunteer of SloCo, but you can read from his words how it all happened.

December: the last month and the last sloth

December is always a relaxing month here at SloCo. Part of the team starts their holidays, and most of us pause our activities to spend time with our friends and families. But before all of that, we collared the latest sloth of the year, found in Sloth City as well, near Gandalf. A beautiful three-fingered sloth that we named Jemima.


Jemima, wearing a collar with a Daily Diary Data Logger.


Thank you for another wonderful year!

We started this project in November 2020 with our first sloth, Sharon, who sadly passed away as a victim of electrocution, proving the necessity of research on the impacts of urbanization on wild sloths. It’s been over three years since then; we’ve had ups and downs, lived, learned, improved our technology, and become more efficient. Change is the only constant, and it’s fine; this is how you grow.


Noah, through the lens of our scope


But one thing that hasn’t changed is the support of our amazing community of sloth supporters worldwide. To all our volunteers, some of whom came from faraway places like Australia; to people who donated for collars and Data Loggers, to the staff at Swansea University, to the VIP subscribers, thank you.

None of this would have been possible without you. Here’s what we’ve achieved together so far in this project since November 2020 (total numbers):

  • 29 total sloths monitored
  • 13 backpacks
  • 30 collars
  • 10 antennas used
  • 21 sloth trackers
  • +1,650 hours of tracking
  • +24,200 data points manually recorded
  • +7.1 billion data points collected by data loggers

Thank you once again for a wonderful 2023, and we hope you continue supporting us in this new year that is just starting!

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!


-SloCo Team


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