brachiation In some arboreal Primates, a form of locomotion in which an animal swings hand over hand from branch to branch. The only true brachiators are the gibbons (Hylobatidae), which are able to move more quickly through the trees than a human can walk on the ground below, but the spider monkey (Ateles, see CEBIDAE) and its relatives use brachiation a good deal in their locomotion. One hypothesis holds that the Hominidae (including humans) are descended from brachiating ancestors.

brachiation In some arboreal primates, a form of locomotion in which an animal swings hand over hand from branch to branch. In those species in which it is developed fully (species of gibbons (Hylobatidae) and apes (Pongidae)), apes are said to be able to move more quickly through the trees than a human can walk on the ground below.