If running on the toes increases speed, the same adaptation would be useful for potential prey animals to escape predators. Pictured here is the foot of a pig. The big toe is completely absent, leaving four toes (two of which are large and two reduced in size - one small toe is visible from this angle). Because the weight of the animal is borne by two toes, this is referred to as a paraxonic foot, and the posture is unguligrade. The artiodactyls (pigs, deer, bison, elk, etc.) all have this type of foot, balancing on the last bone of the toe, much like a ballet dancer. Notice that the two enlarged metatarsals are not fused.