Cats and dogs use their whiskers for a variety of purposes. Whiskers, unlike other types of hair, are thicker and more deeply embedded in the skin. Cats have twelve whiskers arranged in four rows on each side, and can also grow whiskers behind their wrists. Dogs, meanwhile, grow whiskers in more varied patterns and can also grow them above the eye.
Whiskers are primarily used to aid in vision; anything that brushes up against the whisker causes it to vibrate and stimulate the nerves in the hair follicle. In a dark room, a dog or cat can pick up on a nearby wall due to a change in air currents that they sense through their whiskers. Facial whiskers help cats determine if they can fit into a tight space. Whiskers on cats’ legs help them detect prey. Dogs’ facial whiskers serve much the same purpose.
Fun fact: The scientific name for whiskers is vibrissae, derived from the Latin word vibrio which means “to vibrate.”
Fuller, Mary. “What’s the Deal with Whiskers?” Vetstreet.com. Web. 23 May 2012. 1 March 2014. <http://www.vetstreet.com/our-pet-experts/whats-the-deal-with-whiskers>