"Sloth" by Neil Hooting;
used with permission under CC BY 2.0
Sloths are mammals that fall under the order of Pilosa and suborder of Folivora.
One of the most fascinating facts about sloths is that in order for a sloth to keep living on such a limited diet (see dinner section for more!), the sloth maintains a body temperature of 30-34 degrees celsius, and even lower when they are resting! In comparison an average human has an average body temperature of 37 degrees celsius. Who knew sloths were such cool customers!?
Leaves provide little energy, and sloths deal with this by a range of economy measures: the low body temperature we just talked about and a very low metabolic rate--less than half of that expected for a creature of their size.