Dewclaw
A dewclaw is a digit – vestigial in some animals – on the foot of many mammals, birds, and reptiles (including some extinct orders, like certain theropods). It commonly grows higher on the leg than the rest of the foot, such that in digitigrade or unguligrade species, it does not make contact with the ground when the animal is standing. The name refers to the dewclaw's alleged tendency to brush dew away from grass.[1] On dogs and cats, the dewclaws are on the inside of the front legs, similarly to a human's thumb, which shares evolutionary homology.[2] Although many animals have dewclaws, other similar species do not, such as horses, giraffes and the African wild dog.
For the web-comic characters of the same last name, see Kevin and Kell.Cats[edit]
Members of the cat family – including domestic cats[9] and wild cats like the lion[10] – have dewclaws. Generally, a dewclaw grows on the inside of each front leg but not on either hind leg.[11]
The dewclaw on cats is not vestigial. Wild felids use the dewclaw in hunting, where it provides an additional claw with which to catch and hold prey.[10]