A fang is a sharp tooth used for catching prey found on many animals such as wolves and spiders. Spiders, tarantulas, and venomous snakes have hollow fangs. Venom glands fill these hollow fangs with venom so that when these animals catch their prey with their fangs, they paralyze the prey to make it easier to eat. The fangs on a snake can be folded under the skin like a cat's claws. Spider and tarantula fangs are found outside of their mouth instead of inside it.