Giant Sloths Once Ruled Americas Before Human Arrival

Ancient sloths inhabited a wide range of environments—trees, mountains, deserts, boreal forests, and open savannahs. These diverse habitats played a major role in shaping the wide variation in sloth species' sizes. Illustration by Diego Barletta

Elephant-sized sloths once roamed from Alaska to Argentina, carving caves with massive claws and diving into oceans for seagrass meals. These ancient giants, some weighing 8,000 pounds, dominated the Americas for over 30 million years before vanishing around 15,000 years ago—just as humans spread across the continents. A new study published in Science reveals how … Read more