Vibrissae, more commonly known as whiskers, are sensory hair
that generally have a tactile sense, which is equivalent to skin. They grow on
most mammals except monotremes (duck-billed platypus and echidnas) and humans,
though humans still have remnants of the muscles once associated with vibrissae
in their upper lips. Vibrissae serve a number of purposes: such as sense of
touch; detection of danger, air and water currents, and movements of other
animals; and the locating of food.
