Brown-throated three-toed sloth sleeping in cecropia tree, Costa Rica

© Juan Carlos Vindas/Getty Image

Brown-throated three-toed sloth

Costa Rica's lush forests are habitats for two sloth species: Hoffmann's two-toed sloth and the star of today's homepage, the brown-throated three-toed sloth. Despite being larger than many tree-dwelling mammals, three-toed sloths have adapted by reducing their muscle mass and size to thrive on treetops. Their large stomachs have four chambers, which can make up to 30% of their body weight when full. These shaggy critters are so sedentary that algae grow on their coats. This symbiotic relationship provides them with a greenish hue, offering effective camouflage within the rainforest canopy. In 2021, these slow-moving creatures were declared national symbols in Costa Rica. Then-President Carlos Alvarado signed the initiative into law in 2021 to emphasize the sloths' importance in the country's ecosystem.