The sloth family tree once sported a dizzying array of branches, body sizes and lifestyles, from small and limber tree climbers to lumbering bear-sized landlubbers. Why sloth body size was once so ...

A cooling, drying climate turned sloths into giants – before humans potentially drove the huge animals to extinction. Today’s sloths are small, famously sluggish herbivores that move through ...

Today, sloths are slow-moving, tree-dwelling creatures that live in Central and South America and can grow up to 2.5 feet long. Thousands of years ago, however, some sloths walked along the ground ...

Tree sloths have reportedly survived falls of up to 100 feet. However, given that falls from even moderate heights can cause severe damage and some trees in the Amazon Rainforest top out at just ...

For centuries, people encountering sloths for the first time have reacted by ridiculing them. In 1526, Spanish conquistador Gonzalo Fernández de Oviedo y Valdés wrote that the sloths he’d seen ...

Sloths have a reputation for being sluggish and slow, spending most of their lives dozing in trees, but a new study suggests this is one of the enduring secrets of their success. Scientists have ...

Scientists have analyzed ancient DNA and compared more than 400 fossils from 17 natural history museums to figure out how and why extinct sloths got so big. Most of us are familiar sloths ...