involves supporting the body using the forelimbs to hang beneath a tree branch. Thus the body is supported under the arms.
The animal moves about by a hand-over-hand grip, of "arm swinging"
Suspension can be divided into three types:
- exhibited only by the hylobatidae
traditional arm swinging and is very fast
- seen in both New and Old World monkeys, combination of arm swinging and leaping (New World - have a prehensile tail to assist)
- witnessed in great apes, involves a slower form of locomotion. Combination of climbing and swinging is utilized. The orangutan is famous for quadrumanual locomotion "four-handed"
Specific morphological traits for suspension include the following:
- longer upper limbs, including fingers
- short thumbs in the hylobatids for a hook like hand grip
- short, stable lumbar spine
- no tail
- large body size, especially the slow climbers
- broad thorax, not deep
- scapula on dorsum of body
- foramen magnum in intermediate location