49
votes
Do we know all the possible human hair colors?
Melanin is the only biologically coded for pigment amongst mammals and most animals broadly speaking. Some birds are exceptional in this case where reds and greens can be seen (in which case often ...
- 699
39
votes
What would cause red-haired people to become fewer?
Let's consider a possible scenario, with a simplified assumption that red hair is a simple Mendelian recessive trait.
Let's say we have a population that is 10% red hair. Everyone with red hair lives ...
- 44.1k
11
votes
Accepted
Do pulled hair from the root grow back?
There's no harm in plucing a hair, but it won't do you much good
Plucking the hair will indeed get rid of the hair - but only temporarily
"The follicle (the little tube beneath the skin that ...
- 2,380
10
votes
Why is male balding so common in comparison to female balding?
Let's start off by saying that "baldness" is a very broad term... it includes not only hair loss but also miniaturization, which accounts for the majority of the phenotypic "baldness&...
- 2,711
10
votes
Why are bald heads so "shiny"?
Think of what happens when you don't wash your hair for days. It gets oily and greasy. This oil-like substance on your hair is called sebum and mainly works as a lubricant . The Sebaceous glands ...
8
votes
How do disulphide bonds in hair cause curling?
Nice question. I must say it took me many hours to get satisfactory answer.
Hairs are made of keratin molecules, which contain cysteine. Cysteine has thiol (-SH) group, by which it can form disulfide (...
- 14.1k
5
votes
Why does hair turn white but not skin?
The answer to this question has its reason in the hair cycle. Our hair goes through a cycle of growth. At the end of this cycle, the cells in the hair follicle die and have to be replenished before a ...
- 51.5k
4
votes
Accepted
Why do Asian people have black hair and Northern people have golden hair?
All people don't have those hair colors. All people from those Northern countries aren't blond, and there are blond people outside of Northern Europe; I don't know if you count Melanesians as "Asian", ...
- 3,245
3
votes
Accepted
Why does our hair turn white before we get old?
Human hair color depends mostly on two pigments: eumelanin and pheomelanin. Eumelanin has brown and black variants, whereas pheomelanin is reddish/orange. Cells at the base of hair follicles produce ...
3
votes
Accepted
The onset of hair loss in men
Mostly it is because of the scalp and a decrease in the hair follicles ability to maintain production of sturdy hair (keratin along with melanin for hair color). In some cases, it is also genetic such ...
- 815
3
votes
Accepted
How large are the inner ear hairs?
Those are just ordinary hairs growing in your ear, like the kind you find in your nose and, if you are fortunate, on the top of your head. The "hair cells" of the inner ear aren't really "hairs" at ...
- 44.1k
3
votes
What does static electricity generated by plastic combs do to our hair?
The motion of the comb against your hair remove electrons from the hair and deposits them on the comb. The positively charged hair and negatively charge comb now attract each other due to their ...
- 1,351
2
votes
Why did humans lose their fur?
The short answer is that no-one knows. That no-one knows, along with a lot of popular interest, has led to wide ranging speculation. Some of that is well grounded, but much of it is not. Some has been ...
- 191
2
votes
Hair becoming white in one night after tremendous stress
The physiological condition you are looking for is commonly called Marie Antoinette Syndrome.
Under extreme psychological stress, the hair of the person does turn white but not in a single night (...
- 163
2
votes
Accepted
Is Infra Red light safe to use on your scalp?
These are entirely different devices. First off, the Anodyne product is truly far-infrared, emitting at 890 nm (infrared is above ~650-700 nm). However, the hair loss product you linked is far-red/...
- 15.2k
2
votes
Accepted
Whitening of hair at old age
It would be incorrect to assume that
every change has a significance
from an evolutionary point of view. In many cases, the changes could be happening at an age where it does not affect it's ...
- 36
2
votes
Why do hair on head not get pilo-erected?
Piloerection of head hair does happen as often as it occurs elsewhere on the body, but head hair length tends to make it difficult to see. Close observation, especially with short hair, should make it ...
- 191
2
votes
Do individual mammal hairs absorb water?
Researching this answer took me to some strange literature, but it appears to suggest a little bit of both (at least for human hair, which is porous, implying that some water can suffuse through the ...
- 940
2
votes
Why do men have a greater chance of suffering from hair loss?
As per my comment above, some types of hair loss is androgenic, and therefore related to testosterone levels. This is why eunuchs can be resistant to some forms of hair loss.
- 1,289
2
votes
How can you diagnose albinism in a naturally light-colored person?
Short answer
Due to the considerable phenotypic overlap of different types of Oculocutaneous Albinism (OCA), molecular testing using a multigene panel or comprehensive genome sequencing is generally ...
- 121
2
votes
Is hair made of protein or dead cells or both?
I found the answer while trying to write the question. Hopefully this helps others
We usually say that hair is “made” of a protein called keratin—that’s a bit of a simplification. As hairs become ...
- 141
2
votes
Accepted
Aging: Only humans have grey hair?
I don't think it is restricted to humans. Dogs lose hair pigment as well, usually around the muzzle.
This work used graying of hair to discriminate senior dogs.
I don't know which other mammals lose ...
- 707
2
votes
Accepted
How long to regrow hair?
According to https://en.wikipedia.org/wiki/Human_hair_growth:
Scalp hair is known to grow between 0.6cm and 3.36cm per month. The growth rate of scalp hair somewhat depends on age (hair tends to grow ...
- 384
1
vote
Evolutionary selection pressure for human hair patterns?
At least some of it is a side effect of the way human skin develops. Humans actually have the same number and density of hair follicles as great apes, it is merely that our hair develops as short ...
- 412
1
vote
How many hairs per sq. cm. (or inch) do hamsters have on average?
According to Paul et al. (2007), shaved fur patches of male Siberian and Syrian hamsters had a mass of about 12 mg/cm2 dorsally and 3 mg/cm2 ventrally.
This search give me the page.
Fig 1 from Paul ...
- 10.3k
1
vote
Do people with higher body hair growth (eg. Women with hirutism) need more protein?
Not significantly. Most people should have roughly 50g of protein a day, and most diets provide plenty. Larger people require a little more, and activity levels are another factor.
Hair grows ...
- 298
1
vote
What function does a mane serve in animals that possess it?
I am not aware of the evolutionary advantage of the mane in the animals that you mention. In fact, the only reference I could find talks about a predator, not a prey, and thus it might indicate that ...
- 982
1
vote
Identify the fluff that I have found in tea
It's kind of hard to tell from the picture, but maybe it's a variety of Milkweed seed-pod that got into the tea?
- 111
1
vote
What is the structural/chemical difference leading to different shapes in facial/head/pubic hair?
hair shape texture is really easy. the biggest effect is the shape, size, and angle of the hair follicle. Hair with different cross sections have different properties. If hair is stiffer in one plane ...
- 14.3k
Only top scored, non community-wiki answers of a minimum length are eligible