Brachiation is a form of arboreal locomotion

Arboreal locomotion

Arboreal locomotion is the locomotion of animals in trees. In every habitat in which trees are present, animals have evolved to move in them. Some animals may only scale trees occasionally, while others are exclusively arboreal. These habitats pose numerous mechanical challenges to animals...

 in which primate

Primate

A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...

s swing from tree limb to tree limb using only their arms.

Brachiators

The only true brachiators are the lesser ape

Ape

Apes are Old World anthropoid mammals, more specifically a clade of tailless catarrhine primates, belonging to the biological superfamily Hominoidea. The apes are native to Africa and South-east Asia, although in relatively recent times humans have spread all over the world...

s (gibbon

Gibbon

Gibbons are apes in the family Hylobatidae . The family is divided into four genera based on their diploid chromosome number: Hylobates , Hoolock , Nomascus , and Symphalangus . The extinct Bunopithecus sericus is a gibbon or gibbon-like ape which, until recently, was thought to be closely related...

s and siamang

Siamang

The siamang is a tailless, arboreal, black-furred gibbon native to the forests of Malaysia, Thailand, and Sumatra. The largest of the lesser apes, the siamang can be twice the size of other gibbons, reaching 1 m in height, and weighing up to 14 kg...

s). A gibbon can brachiate at speeds as high as 35 mph (55 km/h) and can travel as far as 20 feet (6 m) with each swing. Spider monkey

Spider monkey

Spider monkeys of the genus Ateles are New World monkeys in the subfamily Atelinae, family Atelidae. Like other atelines, they are found in tropical forests of Central and South America, from southern Mexico to Brazil...

s and orangutan

Orangutan

Orangutans are the only exclusively Asian genus of extant great ape. The largest living arboreal animals, they have proportionally longer arms than the other, more terrestrial, great apes. They are among the most intelligent primates and use a variety of sophisticated tools, also making sleeping...

s are considered semibrachiators.

Traits that aid brachiation

Some traits that allow primates to brachiate include short fingernails (instead of claws), inward-closing hook-like fingers, opposable thumbs, long forelimbs, and freely rotating wrists.

Brachiation and great apes

Modern human

Anatomically modern humans

The term anatomically modern humans in paleoanthropology refers to early individuals of Homo sapiens with an appearance consistent with the range of phenotypes in modern humans....

s retain many physical characteristics that suggest a brachiator ancestor, including flexible shoulder joints and fingers well-suited for grasping. In lesser apes, these characteristics were adaptations for brachiation. Although great apes do not normally brachiate (with the exception of orangutan

Orangutan

Orangutans are the only exclusively Asian genus of extant great ape. The largest living arboreal animals, they have proportionally longer arms than the other, more terrestrial, great apes. They are among the most intelligent primates and use a variety of sophisticated tools, also making sleeping...

s), our human anatomy suggests that brachiation may be a preadaptation

Preadaptation

In evolutionary biology, preadaptation describes a situation where a species evolves to use a preexisting structure or trait inherited from an ancestor for a potentially unrelated function...

 to bipedalism, and healthy modern humans are still capable of brachiating. Some children's parks include monkey bars

Jungle gym

The jungle gym, monkey bars, or climbing frame, is a piece of playground equipment made of many pieces of material, such as metal pipe or rope, on which children can climb, hang, or sit. The monkey bar designation refers to the rambunctious, climbing play of monkeys.-History:The first jungle gym...

which children play on by brachiating.