Whiskers are sensitive tactile hairs, and the hair follicles are connected to tactile nerves that help cats sense changes in their surroundings. When hunting in the wild, a cat's whiskers can be used to measure the size of the hole to determine if it can enter.

Cats have three types of hair, the first is the coat, where the neck, back, limbs and tail are exposed. The second is fluff, which grows in softer places such as the inside of the limbs, abdomen and face. Finally there are the tentacles, which grow above the eyes, on the sides of the nose, on the inside of the auricle, and between the paw pads. The tentacles on either side of the nose are the whiskers.

The tentacles, as the name suggests, are of course used to sense the outside world. In general, tentacles are tougher and less prone to falling and breaking, which allows for more accurate transmission of perceived information to the cat. The hairs on the ears and soles of the feet are a little softer than the whiskers because they are more subtle to sense air movement and ground vibrations. Beards need to collect information through touch, so they are relatively hard.

At night, while cats have excellent night vision, whiskers can make them more sensitive to their surroundings, which is very important for the blind as a walking stick.

Therefore, although a cat's whiskers are also used to measure width, it is not measured by the length of the whiskers, but by the changes in airflow and distance to judge the distance of an object from itself. Some people have clipped cats' whiskers and found that they collide and drill holes they can't get into. This is because they are not used to the length of their whiskers being cut off, and hairless cats don't move around because they don't have whiskers.

When many owners play with their cats, they find that the cat's mouth is bulged and the ends of the whiskers are placed in front. Also because they want to accurately perceive the objects they are playing with and their surroundings, they place their whiskers back when eating and drinking, even close to the face, to prevent the whiskers from smudging and affecting their sensitivity. You can do a little experiment by bringing your fingers close to their whiskers and they will pull the whiskers back as they maintain the sensitivity of the whiskers.