Skunks are notorious for their anal scent glands, which they can use as a defensive weapon. They are similar to, though much more developed than, the glands found in species of the family Mustelidae. Skunks have two glands, one on each side of the anus. These glands produce a mixture of sulfur-containing chemicals such as thiols, traditionally called mercaptans, which have a highly offensive smell. The odor of the fluid is strong enough to ward off bears and other potential attackers and can be difficult to remove from clothing. Muscles located next to the scent glands allow them to spray with a high degree of accuracy, as far as 3 m (10 ft). The smell aside, the spray can cause irritation and even temporary blindness, and is sufficiently powerful to be detected by a human nose up to a mile down wind.