We're still in the middle of the Urban Sloth Project, but we wanted to share what the data is showing so far.

Martita's GPS data proved a road crossing was dangerous for sloths. Now there's a canopy bridge there and howler monkeys used it within 24 hours.

A new study published may finally provide some clues.

When we think about the loss of forests, we usually imagine clear-cut deforestation. But across Latin America, another kind of forest loss is also happening…

From the trees above a busy beach cantina to the edges of the urban forest, Tender’s life gave us a rare glimpse into how sloths grow, move, and adapt in human-shaped landscapes. This is the story of a gentle sloth, the community that surrounded him, and the lessons he left behind.

Trying to count sloths in a rainforest is quite hard: they move slowly, blend perfectly with the leaves, and spend their days tucked high in the canopy. But now, technology is giving conservationists and researchers a powerful new ally: drones that can see heat.

If there’s one thing fieldwork teaches you, it’s that nothing ever goes entirely to plan, and that’s exactly what makes it exciting.

We don’t know how many sloths there are.
We don’t even know how many there should be.
And that’s a problem.

Vanderhoeven, E.A., Florida, M., Cliffe, R.N., Guzmán, J., Notarnicola, J. and Kartzinel, T.R., 2025. Host specificity of gastrointestinal parasites in free-ranging sloths from Costa Rica. PeerJ, 13, p.e19408.

Last week, we went to the primary forests in search of new sloths to collar and monitor for the Urban Sloth Project.

Tender is no ordinary sloth. He’s a young, sweet explorer living near a beach bar in Costa Rica’s South Caribbean. But his story starts with someone equally extraordinary: his mother, Tiki.

Cliffe, R.N., Ewart, H.E., Scantlebury, D.M., Kennedy, S., Avey-Arroyo, J., Mindich, D. and Wilson, R.P., 2024. Sloth metabolism may make survival untenable under climate change scenarios. PeerJ, 12, p.e18168.

Studying the GPS locations of an animal that doesn’t move much is challenging compared to studying species that travel a lot, such as whales and cheetahs. When studying sloths, accuracy is what we need to focus on.

Social media is filled with photos and videos of people holding sloths (or other wildlife), and we are investigating the reasons behind this behavior, as well as public perceptions and experiences regarding encounters with sloths.

This lovely pair was discovered in the beautiful garden of a local resort.   The owner contacted Dr. Cliffe, founder and executive director of The Sloth Conservation Foundation.

Many locals in the beach town of Puerto Viejo de Talamanca, where the Sloth Conservation Foundation is located, help Dr. Rebecca Cliffe and her team by alerting her when they find a sloth.

Back in June 2023, we ventured into the lush rainforest of La Selva Biological Station and Reserve to fit GPS collars on three sloths there: George, Misty, and Selvina.

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.

Habitat surveys are an essential part of the Urban Sloth Project (USP). In these surveys, we make eight squares, each 100 square meters, in the areas where sloths live. We collect GPS locations of the sloths and study the trees in these squares.

Are sloths drinking more water than before? Is the smoke from cars affecting the delicate micro-ecosystems of green algae and moths that sloths have in their fur? Are sloths affected by artificial lights?