Leather is the skin of an animal made into a durable material by tanning. The skins of cows, pigs, and goats are often used to make leather. Skins of snakes, alligators or crocodiles, and ostriches are sometimes used to make fancier leather. Shoes, bags, clothes, and balls are often made of leather. Sometimes people make leather out of whales, ducks, giraffes, and African elephants, but all of these ways of making leather are very simple but can also be very hard and rare sometimes.