Digitigrade

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.

Plantigrade animals, such as humans, normally walk with the soles of their feet on the ground. Unguligrade animals, such as horses and cattle, walk only on the distal-most tips of their digits. Digitigrade animals walk on their distal and intermediate phalanges; more than one segment of the digit makes contact with the ground, either directly (as in birds) or via paw-pads (as in dogs and cats).

Examples of digitigrade and semi-digitigrade animal species

• Mesonychidae
• Dinosaurs (digitigrade and semi-digitigrade)
  • Birds (except for loons, grebes and penguins which are plantigrade)
• Suina (semi-digitigrade)
• Hippopotamidae (semi-digitigrade)
• Pakicetus
• Indohyus
• Thylacine
• Carnivora:
  • Felidae
  • Hyenas
  • Mongooses
  • Canidae
• Derived hyaenodonts (range from digitigrade to semidigitigrade: ancestrally plantigrade)
• Elephants (semi-digitigrade)
• Capybaras (semi-digitigrade)
• Trucidocynodon (semi-digitigrade at least in the forelimbs)
• Certain primates (including some monkeys and lemurs)