Gibbons are the animals we think of when we picture primates swinging gracefully through the rain forest.

These acrobatic mammals, endemic to the dense forests of southern Asia, are perfectly adapted to life in the trees and rarely descend to the ground. They have strong, hook-shaped hands for grasping branches, comically outsize arms for reaching faraway limbs, and long, powerful legs for propelling and gasping. Their shoulder joints are even specially adapted to allow greater range of motion when swinging.

Their dramatic form of locomotion, called brachiating, can move gibbons through the jungle at up to 35 miles an hour, bridging gaps as wide as 50 feet with a single swinging leap. Brachiating also gives gibbons the unique advantage of being able