knucklewalking

Knuckle-walking is a form of quadrupedal locomotion in which an animal moves on all fours with weight borne on the knuckles of the forelimbs. In this gait, the fingers are flexed and the palm is not used for support, while the wrists are kept extended to create a relatively rigid forelimb for pushing the body forward.

The behavior is most closely associated with great apes. It is best documented in chimpanzees (Pan troglodytes) and gorillas (Gorilla spp.), where knuckle-walking provides a stable means of ground travel while preserving the long, flexible fingers needed for arboreal and suspensory activities. The contact surfaces are generally the dorsal aspects of the finger joints near the knuckles, rather than the palms.

From an evolutionary perspective, knuckle-walking has been proposed as a potential primitive locomotor trait of the common ancestor of African apes and humans. This view is debated. Some researchers argue that knuckle-walking evolved independently in chimpanzees and gorillas as a terrestrial adaptation, while others contend that an ancestral knuckle-walking pattern was retained or modified differently across lineages. The fossil record offers limited direct evidence for knuckle-walking, and interpretations of early hominin wrist morphology remain contested.

In modern humans, sustained knuckle-walking is not typical. Human locomotion is primarily bipedal, and knuckle-walking is not a routine mode of movement outside of unusual or constrained situations.