One of four for a bat or a cat

FANG

Think of the sharp, pointed teeth found in the mouths of certain animals, often used for biting or holding prey. Vampires are also known for having a pair of these.

A bat and a cat both have four of these sharp, pointed teeth. The clue plays on the word "fang," which is a common term for the long canine teeth found in these animals. It’s a straightforward definition where "one of four" hints at counting their fangs—two on top, two on bottom.