Egg tooth

An egg tooth is a temporary, sharp projection present on the bill or snout of an oviparous animal at hatching.

[2] When it is close to hatching, a chick uses its egg tooth to pierce the air sac between the membrane and the eggshell.

They are strong enough at the time of hatching to use their legs and feet to crack open the egg.

The egg tooth is used to tear open the inner membrane; the baby crocodile can then push its way through the outer shell.

If conditions are particularly dry that year, the inner membrane may be too tough for the crocodile to break through, and without assistance it will simply die inside the egg.