Elephant

Legs and feet
An elephant's legs are great straight pillars, as they must be to support its bulk. The elephant needs less muscular power to stand because of its straight legs and large pad-like feet. For this reason, an elephant can stand for very long periods of time without tiring. In fact, African elephants rarely lie down unless they are sick or wounded. Indian elephants, in contrast, lie down frequently.
The feet of an elephant are nearly round. African elephants have three nails on each hind foot, and four on each front foot. Indian elephants have four nails on each hind foot and five on each front foot. Beneath the bones of the foot is a tough, gelatinous material that acts as a cushion or shock absorber. Under the elephant's weight, the foot swells, but it gets smaller when the weight is removed. An elephant can sink deep into mud, but can pull its legs out readily because its feet become smaller when they are lifted.