Why do some animals have whiskers?

Primarily sensory tools, whiskers help animals collect information about their environment. Dense packets of nerves at the base of each whisker feed into a specific pathway, picking up tiny vibrations. They are used to sense objects and air currents, alerting them to approaching dangers, particularly in the dark. Different species use their whiskers for slightly different purposes. Many predators, like seals and shrews, use theirs to detect prey. Rats can move their whiskers rapidly, scanning their surroundings to build up mental maps. Cats use them to judge whether they can squeeze into a small space. Whiskers can also fulfil a social function – for example, dogs show fear by flaring out their whiskers.