There is usually a dark midline along the neck and back and a light streak between the dark orbital rings. Head and eyes are round and small ears almost hidden by fur. Fore and hind limbs are about equal in length. All digits have nails except the second digit of the foot has a claw. The thumb is perpendicular to the other fingers and the great toe points slightly backwards.
Muscles enable effortless hand grasp and rigidly clenched feet.
Storage channels for blood in hands and feet enable it to remain clenched without tiring for long periods of time. Nocturnal and arboreal, it seldom descends to the ground. It sleeps curled up in the fork of a tree or clump of bamboo. It walks hand over feet over hand along branches, usually slowly by it can go faster. Though appearing slow, it can strike with speed.