Skunk spray toxicosis: An odiferous tale
A SKUNK'S LINE OF DEFENSE
Skunks are docile but will defend themselves when threatened. A skunk's first line of defense is defensive posturing. A skunk will hiss, stamp its feet, and raise its tail as a warning. If the warnings are ignored, a skunk will spray anal gland secretions (referred to as either spray or musk).Skunks have two anal glands, one on each side of the anus. The anal gland secretions contain a mixture of sulfur-containing thiols. The odor—which has been described as similar to that of a combination of rotten eggs, garlic, and burnt rubber—tends to drive away most predators.2 Skunks can spray these secretions 7 to 15 ft (2 to 5 meters) and are highly accurate in their aim. Getting sprayed by a skunk is commonly called being skunked. Skunk spray has been used as a biological weapon.2
The skunk's anal gland secretions contain seven major volatile components: three major thiols, three major thioacetates, and a methylquinoline. These are divided into thiols and acetate derivatives of the thiols. Two of these thiols, (E)-2-butene-1-thiol and 3-methyl-1-butanethiol, are responsible for the repellent odor. These two thiols constitute 51% to 70% of the anal gland secretions.
The thioacetates are not as initially odiferous on contact but are converted to more potent thiols with the addition of water. This chemical reaction may explain why some animals continue to smell skunky after a bath—thioacetates trapped in fur continue to release thiols under damp conditions.
The seventh component is an alkaloid 2-methylquinoline, which is not as volatile as the thiols and has a nitrogenous base. The chemical composition and percentages of the volatile components may vary among skunk species. Numerous minor components differ among individual skunks and species.3,4