A skunk's most infamous defense mechanism is his spray -- a pungent liquid with which he douses would-be predators. This spray, also known by the chemical name n-butyl mercaptan, clings to skin and fur and emits a foul odor. While skunks produce this liquid chemical inside their bodies, they don't have an infinite supply at any given time.
What Spray Does
N-butyl mercaptan, more commonly known simply as "skunk spray," is produced by special glands surrounding two sacs in the skunk's anus. As the glands produce skunk spray -- a yellow-tinged liquid sometimes mistaken for urine -- it builds up and is stored in these sacs. The oily compound smells bad enough as it is, but when it mixes with water, a chemical reaction makes the odor even more pronounced, so an animal's efforts to wash off the spray can easily backfire.
When Skunks Shoot
Skunks use their liquid spray as a defense mechanism, not as a way of starting a fight. When a skunk feels threatened, he turns his back to his would-be predator, raises his tail and shoots a liquid mist of his spray in the predator's direction. This spray can shoot 10 to 15 feet, coating his attacker and the area around him with a repulsive odor and giving him the opportunity to slink away. Skunks won't necessarily spray unless they feel they have to -- their spray sacs only store about five spray's worth of liquid, and it can a week or longer to replenish their stores.
Feel the Burn
While the chemical makeup of skunk spray gives it a foul odor, smell isn't the only way in which it wards off predators. When an animal is sprayed in or near the face, the spray can cause serious pain and discomfort. Animals are liable to vomit and fall temporarily ill, and if they are sprayed in the eyes, it can burn and even rob them of their sight temporarily. N-butyl mercaptan is ultimately a powerful chemical that does more than simply smell bad.
Other Defense Mechanisms
Because a skunk can only produce and store so much spray in a certain amount of time, he generally uses it as a last resort -- not a first. Skunks are largely nocturnal animals that operate under cover of darkness, using their black fur to their advantage. They will try to warn away would-be predators with other defense mechanisms, like hissing, before resorting to spraying. Because of their distinct black and white fur patterns, skunks are easily recognizable to animals that have been sprayed in the past, and may be avoided by animals that have learned firsthand what the spray is capable of.
Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.