Egg tooth (nonfiction)

In some egg-laying animals, the egg tooth is a small, sharp, cranial protuberance used by offspring to break or tear through the egg (nonfiction)'s surface during hatching.

It is present in most birds and reptiles, and similar structures exist in monotremes, Eleutherodactyl frogs, and spiders.

Some lizards and snakes develop a true tooth that is shed after use; other reptiles and birds generally develop an analogous epidermal horn that is reabsorbed or falls off.