plantigrade

Plantigrade refers to a mode of locomotion in which an animal bears weight on the full sole of the foot, including the heel and the toes, with the entire plantar surface contacting the ground during stance. The term comes from Latin planta, sole of the foot, and gradi, to walk. This contrasts with digitigrade locomotion, where weight is borne on the toes, and unguligrade locomotion, where weight rests on the hooves.

In a plantigrade gait, the foot lands with the heel contacting first and the whole sole resting on the ground. This arrangement provides stability and a broad base of support, which is advantageous for climbing, manipulating terrain, and precise foot placement on uneven surfaces. The trade-off is typically reduced stride length and maximum running speed compared with digitigrade and unguligrade forms.

Examples of plantigrade animals include humans and bears, as well as many other mammals that walk with the entire sole in contact with the ground. Plantigrade posture is considered the more primitive condition in mammalian evolution, from which more specialized digitigrade and unguligrade forms have evolved in lineages focused on speed and long-distance running.

Overall, plantigrady reflects a balance between stability and versatility, facilitating activities such as climbing, foraging, and deliberate movement across varied terrains.