Hoofed describes an animal that has hooves instead of paws, claws, or feet like ours. A hoof is a hard, thick covering made of keratin (the same material as your fingernails) that protects the ends of certain animals' legs. Horses, deer, cattle, pigs, goats, and sheep are all hoofed animals.

Scientists divide hoofed animals into two main groups based on their toes. Animals with an even number of toes, like deer and cows, have cloven hooves that split down the middle. Animals with an odd number of toes, like horses and zebras, have hooves built around one main toe. A horse's hoof is actually one large toe, though its ancient ancestors had five toes like many other mammals.

Hooves evolved to help these animals run fast across hard ground. A hoof acts like a built-in shoe that never wears out because it keeps growing, just like your fingernails. Wild horses keep their hooves trimmed naturally by walking on rocks and hard surfaces, but domestic horses need a farrier (a person who trims and shoes hooves) to keep their hooves healthy.