Why do people have hair on their arms/legs?

  • Thread starter Pengwuino
  • Start date
  • Tags
    Hair
In summary, the presence of hair on our arms and legs is likely an adaptation for warmth and to act as a sensor for our nerves. It is also a warning system for potential injuries. Some people may have more or less hair on their arms and legs depending on their genetics and grooming habits. The amount of hair on our bodies can vary, with some people having hair on their upper arms and legs while others do not. The function of hair on different parts of our bodies may also vary.
  • #1
Pengwuino
Gold Member
5,124
20
Why do people have hair on their arms/legs? And why does it only seem to grow on half your arm?
 
Biology news on Phys.org
  • #2
I think first would be for warmth. And being that the lower arms and legs are farthest away from the main body, hair should be a bit thicker there.
Its also a sensor for your nerves. I have a friend with alopecia{no hair at all} he gets more cuts, cause he dosen't have the pre-warning system.
 
Last edited:
  • #3
He gets cuts where?
 
  • #4
Just about everywhere that a normal person would of had that split second warning they are about to hit something. And that would include heat{burns}, that quick little singe of hair that warns us to back off.
 
  • #5
Pengwuino said:
Why do people have hair on their arms/legs? And why does it only seem to grow on half your arm?
I expect that it is an adaptation. Here's an interesting article - http://en.wikipedia.org/wiki/Hair

I have seen some men with relatively dense hair on their upper arms and legs, and also their backs.

My legs have hair, and my forearms have hair, but not my upper arms. I have a fair amount of hair on my chest, and some on my abdomen, but probably not as much as brewnog. :biggrin: I think on my upper arms and legs, the fact that I wear clothes wears away the hair.

Of course, my face and scalp have a fair amount of hair. :biggrin:

My beard keeps my face and neck warm in winter and cool in the summer.
 
  • #6
hypatia said:
Just about everywhere that a normal person would of had that split second warning they are about to hit something. And that would include heat{burns}, that quick little singe of hair that warns us to back off.
Well, I don't know about your hypothesis :uhh: You'd have to have heavy long and curly hairs to notice anything! I can't imagine anyone having a split second warning that they are about to cut themselves with a knife because of the miserable little hairs on the top of your fingers. When you are already burning the hairs on your arms I'd think the heat of it would be a pretty good warning sign.
 
  • #7
I thought he meant with the hair on half the arm, about how you don't have hair on the bottom part of you arm. If you stick your arms out, palm-down, what's on the bottom, there is no hair.
 
  • #8
Monique, if you slightly touch the hairs on your arm, you feel it, no matter how short they are. And no I'm talking about cutting yourself with a knife, more like, brushing your leg near a ruff object..if you have hair on your leg..you get a warning.
And its not really my hypothesis, it what the guy told me when I noticed so many scars on him.
 
  • #9
But the hair on my arm are completely flat against my skin. The only difference could be that the signal is amplified by the hairs, since the hairs can move in different directions and thus sensitizes the skin.

So let's do a study: who of the women here at this forum don't shave/wax their arm/leg hair and do they have extra scarring?
 
  • #10
where do you have most hair except ur head ?
 
  • #11
hypatia said:
Monique, if you slightly touch the hairs on your arm, you feel it, no matter how short they are. And no I'm talking about cutting yourself with a knife, more like, brushing your leg near a ruff object..if you have hair on your leg..you get a warning.
And its not really my hypothesis, it what the guy told me when I noticed so many scars on him.
I don't suddenly get more cuts on my legs when I shave them, and competitive body-builders shave their entire bodies without winding up covered in cuts and scrapes. :confused: By the time you're brushing the hairs on your body, it seems too late to do anything much about it. I think your friend is more likely just a bit more klutzy than the rest of us and is trying to make excuses.
 

1. Why do people have hair on their arms and legs?

The presence of hair on the arms and legs is a result of evolution. In the past, humans had much more body hair, which helped to keep them warm and protect their skin from environmental hazards. Although humans have evolved to have less body hair overall, hair on the arms and legs still serves as protection from the elements.

2. Does arm and leg hair serve any purpose?

Yes, arm and leg hair serves several important purposes. It provides protection from sun exposure and helps to regulate body temperature. It also helps to prevent friction and irritation between the skin and clothing.

3. Why do some people have more arm and leg hair than others?

The amount of arm and leg hair a person has is determined by genetics. Some people have a higher concentration of hair follicles on their arms and legs, while others have fewer. Hormonal changes during puberty can also affect the amount of arm and leg hair a person has.

4. Is there any benefit to removing arm and leg hair?

Removing arm and leg hair is a personal choice and there is no medical benefit to doing so. Some people choose to remove hair for aesthetic or cultural reasons, while others prefer to keep their natural hair. However, it is important to note that hair removal methods such as shaving or waxing can lead to skin irritation or infections if not done properly.

5. Can the amount of arm and leg hair change over time?

As mentioned before, hormonal changes during puberty can affect the amount of arm and leg hair a person has. Additionally, hormonal changes during pregnancy or menopause can also lead to changes in the amount of body hair. Some medical conditions or medications can also cause changes in body hair growth.

Similar threads

Replies
11
Views
672
  • Biology and Medical
Replies
7
Views
1K
  • Biology and Medical
Replies
2
Views
1K
  • Biology and Medical
Replies
16
Views
6K
  • Biology and Medical
Replies
3
Views
2K
Replies
11
Views
1K
Replies
2
Views
3K
  • Biology and Medical
Replies
13
Views
21K
  • Biology and Medical
9
Replies
287
Views
18K
  • Introductory Physics Homework Help
Replies
6
Views
558
Back
Top