Why do we get Goosebumps ?

Goosebumps are often seen in cold weather, but some other events like excitement or being scared can also cause it. Is there any reason behind it or it just happens. Everything in human body is for some reason, so there must be some importance of this reaction. Normally evolution takes away any unused feature, just as we have lost our tails. So there must be a use of this unique feature known as "Goosebumps".

Biology of Goosebumps

There are tiny muscles in our skin just under the hair follicles. Some conditions like sudden cold or getting scared activates these muscles to contract, which makes the tiny hairs stand up with tiny bumps on the skin.

Why do sudden cold atmosphere cause goosebumps ?
Our body radiates more heat when the hair lie flat on the skin surface. If the hair strands stand high then it saves the heat near skin to save ourselves from outer cold environment. However this feature is more useful in our ancestors like monkeys and gorillas, as they have a better hair coat over their skin.

Why do feeling scared cause goosebumps ?
Explanation to this fact is interesting. Feeling scared or threatened is something where we need to decide between "fight or flight". Here goosebumps can make us look bigger to make our opponent think twice before harming us. This feature is again less used in humans as we have shorter and lesser body hair. Our ancestors must have used this feature, just like cats do it before they engage in a fight.

Our Emotions can also cause goosebumps
Some of you must have noticed that listening to national anthem in a jam-packed stadium can easily give you goosebumps. Certain feelings that make you full of energy suddenly can cause goosebumps. Even getting intimate with someone can also cause it, sometimes even a touch of opposite sex is sufficient to get goosebumps. Sometimes some memories, some old song, or standing at a podium can give you goosebumps as all of these events are full of emotions.

Here you must be thinking that how does cold and some emotions cause goosebumps. The truth lies in an important hormone of animal body, known as Adrenaline. This hormone is secreted by our adrenal glands in following situations

• Feeilng of extreme or sudden cold
• Feeling fearful
• Emotions like anger, excitement

As the adrenaline is released our body automatically prepares for "fight or flight" mechanism, which causes appearance of tears, trembling hands, sweaty palms and increase in heart beat with rising blood pressure. Other most important reaction of adrenaline release if goosebumps. Adrenaline contracts the smalls muscles in skin automatically and causes goosebumps.

Goosebumps can be best seen in porcupines, which raise their quills when threatened. These quills are nothing but hairs.