thick. They would have resembled no group of living animals. Early mesonychians probably walked on the flats of their feet (plantigrade), while later ones walked on their toes (digitigrade). These later mesonychians had hooves, one on each toe, with four toes on each foot. The foot was compressed for efficient running with the axis between the third and fourth toes (paraxonic); it would have looked something like a hoofed paw.

Mesonychians varied in size; some species