When you imagine a sloth, you probably think of a simple, lazy creature that does very little other than sleep all day. In fact, you might wonder how such an animal survives in the wild at all. Even the very name “sloth” in most languages translates as a version of lazy. In 1749 when sloths were first described in the scientific literature they were labelled as “the lowest form of existence” – it is little surprising that sloths have been subject to such profound speculation and misinterpretation; “sloths are slow because they eat leaves that drug them”; “sloths are so stupid that they mistake their own arm for a tree branch and, grabbing it, fall”; “if you cut the head off a sloth, the heart will continue to beat for 15 minutes……”. I have heard it all. But what does it really mean to be a sloth? Why are they so slow? And why does it work?