Britannica Sources used in this answer

How do orangutans move through the forest canopy?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

An illustration of a female Bornean orangutan (Pongo pygmaeus) with long reddish-brown fur, hanging from tree branches with one arm extended upward and one leg hooked over a branch. A scale bar at the bottom shows lengths of 30 centimeters and 12 inches for size reference. — orangutan Female orangutans (*Pongo*) have the longest breeding interval of any mammal, giving birth on average once every eight years.

Orangutans are primarily arboreal animals, spending more than 90 percent of their time in the trees. To move through the forest canopy, they typically scramble by using all four hands and feet, a method for which they are well-adapted due to their flexible hip joints and hooklike hands and feet with opposable big toes. Because they grip vertical tree trunks equally well with both their forelimbs and hind limbs, they were historically referred to as "four-handed" or quadrumanal.12

While scrambling is their primary mode of travel, orangutans also occasionally swing through the trees using only their arms, a form of locomotion known as brachiation. Although they possess proportionately the longest arms of any great ape, they do not rely on this method as exclusively as some other primates. When on the ground, orangutans are relatively slow and move by walking on their closed fists or extended palms rather than by knuckle-walking like African apes.13