Imagine you leave for work and, as you exit your front door, you encounter a primate hanging from the gutter of your house. It suspends itself with very long arms but has a comparatively small body (compared to overall size) and no tail. It smiles at you and see that it has a 2-1-2-3 dental formula. It then leaps acrobatically to a nearby tree and heads off down the street using a hand-over-hand movement (brachiation) punctuated by very acrobatic leaps from tree to tree. You decide:.