Everyone experiences goosebumps from time to time. When it happens, the hairs on your arms, legs, or torso stand up straight. The hairs also pull up a little bump of skin, the hair follicle, up with them.

The medical terms for goosebumps are piloerection, cutis anserina, and horripilation. The term “goosebumps” is most widely used because it’s easy to remember: The little bumps that form on your skin when this phenomenon happens look like the skin of a plucked bird.

As you may have noticed, goosebumps tend to form when you’re cold. They also form when you experience a strong emotional feeling, such as extreme fear, sadness, joy, and sexual arousal.

Goosebumps may also occur during times of physical exertion, even for small activities, like when you’re having a bowel movement. This is because the physical exertion activates your sympathetic, or instinctual, nervous system. Sometimes, goosebumps may crop up for no reason at all.

Many animals also experience what could be categorized as goosebumps, including porcupines and dogs. In these cases, goosebumps are a bodily response to situations where it’s advantageous to appear larger and stronger, such as during a confrontation or courtship.

In humans, experts believe goosebumps are a product of evolution working in a similar way as they’re meant to in nonhuman animals.

On the most basic level, goosebumps can help keep you warm. When you’re cold, the muscle movements that can trigger goosebumps will also warm your body.

In animals, this action also raises hairs in a way that traps air to create insulation. In people, this effect doesn’t do quite as much. Humans have much less body hair than many other nonhuman animals with hair.

As your body heats up, your goosebumps will slowly begin to disappear. The same goes for bodily exertions that can cause goosebumps, such as having a bowel movement. After a bowel movement, goosebumps will disappear.

Goosebumps caused by emotion

When you’re experiencing extreme emotions, the human body responds in a variety of ways. Two common responses include increased electrical activity in the muscles just under the skin and increased depth or heaviness of breathing. These two responses appear to trigger goosebumps.

With these responses, you may also notice sweating or an increase in your heart rate. Intense emotions and their associated responses can be elicited by your what you think, hear, see, smell, taste, or touch.

Goosebumps are also associated with the state of feeling emotionally touched in either a joyful or sad way. Sometimes it can be both at the same time.

One study suggests that viewing social stimuli, such as an emotional conversation between actors in a film, is more closely associated with goosebumps than just hearing something, such as a song that’s emotionally touching.

In most cases, goosebumps are nothing more than a temporary nuisance. However, goosebumps can be a sign of a long-lasting or serious medical condition. For example, goosebumps can also be a sign of: