For example, a Walrus uses tusks to pull its large body out of the water onto ice flows. Members of the cat family use their teeth to carry their young from place to place. Teeth can also be used in defense and protection. Dog's will bite if provoked and venomous snakes use their hollow fangs to inject poison. Some fish use their mouth and relatively small teeth to protect their young until they are larger and fast enough to avoid being eaten by predators.
Some animals use their teeth to capture prey.
The Great White Shark has many sets of razor-sharp teeth that slant inward. This makes it difficult for the prey to escape their grasp. Other fish have protrusible jaws that also help capture prey. I know that the arrangement of teeth can change the way a person sounds when they talk or sing. This is why some recording artists sound different after they have had orthodontic treatment.