digitigrade

In terrestrial vertebrates, digitigrade ( ) locomotion is walking or running on the toes (from the Latin digitus, 'finger', and gradior, 'walk'). A digitigrade animal is one that stands or walks with its toes (phalanges) on the ground, and the rest of its foot lifted. Digitigrades include birds (what many see as bird's knees are actually ankles), cats, dogs, and many other mammals, but not plantigrades (such as humans) or unguligrades (such as horses). Digitigrades generally move more quickly than other animals.

thumb|Comparison of lower limb structure. From left to right: plantigrade, digitigrade and unguligrade. In red the basipod, in violet the metapodia, in yellow the phalanges, in brown the keratin nails. There are structural differences between the limb anatomy of plantigrades, unguligrades, and digitigrades. Digitigrade and unguligrade animals have relatively long carpals and tarsals, and the bones which correspond to the human ankle are thus set much higher in the limb than in a human. In a digitigrade animal, this effectively lengthens the foot, so much so that what are often thought of as a digitigrade animal's "hands" and "feet" correspond to only the human fingers or toes. Digitigrade locomotion is responsible for the distinctive hooked shape of dog legs.