Rebecca Cliffe

Rebecca Cliffe is a conservation biologist and leading authority on sloth ecology. She began her work in Costa Rica at age 18 and has since dedicated her career to protecting wild sloths.

Rebecca holds a Ph.D. in bioscience from Swansea University and is the founder and executive director of the Sloth Conservation Foundation (SloCo), now the world’s largest organization dedicated to sloth conservation. She pioneered the first long-term field studies of wild sloths, creating what is now the most comprehensive dataset on sloth ecology in existence. Her research has transformed understanding of sloth biology and continues to guide conservation research, policy and practice.

Through SloCo, Rebecca started the Connected Gardens project, an innovative community-led conservation model that restores canopy connectivity across private lands. The project has created the world’s largest network of canopy bridges and has shown how thousands of small actions by individual landowners can create landscape-scale ecological change. Her work has informed wildlife regulations, helped secure legal protections for sloths in Costa Rica, and she is now leading efforts to combat the international trade in wild-caught sloths. She is also leading Costa Rica’s first national sloth census and helping shape policies that integrate wildlife connectivity into infrastructure planning.

Rebecca received the Future For Nature Award in 2022 and an honorary doctor of science degree in 2024. She was also a finalist for the 2026 St Andrews Prize for the Environment. Her work has been featured on NBC’s Today Show, 60 Minutes, BBC and National Geographic.