mouth

Relaxed cat

A muzzled German Shepherd.

A muzzle is a device that is placed over the snout of an animal to keep it from biting or otherwise opening its mouth.

The bill of a scavenger—the vulture.

The beak—otherwise known as the bill or rostrum—is an external anatomical structure which serves as the mouth in some animals. It is a distinctive feature of birds and, in addition to eating, is used by them for grooming, manipulating objects, killing prey, probing for food, courtship, and feeding their young.