Placentals reverse this, avoiding two energy conversions with associated losses by diffusing food digested by the mother directly to the blood of the fetus. Planigrade Walk on palms or flat feet. Lengthen appendage and add another joint to increase speed of running, yet retain some manipulative functions. Digitigrade animals can climb, dig or hold prey, but not particularly well. Examples include cats and dogs.
Humans walk planigrade but sprint digitigrade.
Unguligrade - Walk on point of toes or toenails. Metatarsals and metacarpals are greatly elongated, the digits are reduced in number, but increased in size and strength effectively adding extra segments to the legs. Examples include deer, cattle, horses, goats, camels, etc.