• Question from:Nick

Hi there

Amazing site. I was reading through some old posts and came across this one about the purpose of arm and leg hair.

http://www.askabiologist.org.uk/answers … hp?id=1119

You often hear people saying that we have body hair to keep us warm when they stand on end. I'm certain I've heard of a study somewhere that this is vestigial and is ineffective in heat retention in humans.

Ever since studying parasites at university I have become convinced that we have retained these hairs as a mechanism to detect parasites that land on us as they attempt to feed or enter. They brush against the hairs thus alerting us to their presence and it gives us a chance to swat them away.

Does this seem reasonable? Do you know of any studies to support this idea? Anecdotally I do seem to get more mosquito bites on my knuckles and the hairless parts of the back of my fingers than on the rest of my hand (rarely the palm though - I assume the skin is too tough).

Any thoughts are greatly appreciated as always.

Thank you.

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Yes you are right. In addition to Paolo's points, hair does have other functions including tactile ones. Thicker hair, for example on the legs and arms, does act as a barrier to skin parasites like mosquitoes. Finer hair in the nose also acts as a barrier to things like dust.

In humans the role of hair in heat retention is tiny but I would say there definitely is one. I guess how effectual varies from person to person, climate, etc.