Why do I get goose bumps?
Goose bumps occur when your body is trying to warm itself up. When you get cold enough, your nerves send a signal to tiny muscles that are connected to the base of your hair follicles. The signal tells the tiny muscles to contract, and this makes the hair stand straight up. This muscle contraction also makes the skin pucker so that you look something like a plucked goose – hence the term “goose bumps”.
Unfortunately, this doesn’t warm you very much. But for animals that have a lot of fur, making their hair stand on end can warm them significantly. It helps to trap a layer of air close to their bodies and this insulates them from the cold.