Feeds

Why isn't pubic hair the same colour as hair on your head?

Got you by the short and curlies

Application security programs and practises

Also in this week's column:

Why isn't pubic hair the same colour as hair on your head?

Asked by Hannah Swain of The Hague, The Netherlands

Just as with skin, the colour of hair is determined by the amount of melanin in the outer layer (cortex) of each hair. Melanin is a protein that has colour. Black hair has the greatest amount of melanin. White hair has no melanin. Hair gets its colour from the two types of melanin that create the variety of hair colors we see.

Eumelanin (sometimes called black/brown melanin) is the darkest melanin and the most commonly found in humans. Phaeomelanin (sometimes called red melanin) is the lighter melanin. One's hair color is the ratio of eumelanin to phaeomelanin. A high amount of eumelanin with little phaeomelanin results in black or brown hair. As the ratio of eumelanin to phaeomelanin lessens, the result is red, ginger, and blonde hair.

This ratio varies enormously among humans. This is why everyone's hair is just a little different.

Melanin is produced by a group of specialized cells called melanocytes. These cells are located near the hair bulb. They collect and form bundles of a pigment protein complex called melanosomes. The size, type, and distribution of the melanosomes will determine the type of melanin produced and in which ratio. The type of melanin of a person's hair is inherited.

Melanin also varies in the hair of different parts of the body. This is why pubic hair is sometimes a slightly different colour from hair elsewhere. The absence of melanin later in life causes white hair. White hair may appear on some parts of the body before others because there is variation in this too.

Interesting facts

  • The average human hair is 91 per cent protein.
  • The average human hair is composed of 45 per cent carbon, 27.9 per cent oxygen, 15.1 per cent nitrogen, 6.6 per cent hydrogen, and 5.2 per cent sulfur.

Stephen Juan, Ph.D. is an anthropologist at the University of Sydney. Email your Odd Body questions to s.juan@edfac.usyd.edu.au

Build a business case: developing custom apps

More from The Register

next story
Just TWO climate committee MPs contradict IPCC: The two with SCIENCE degrees
'Greenhouse effect is real, but as for the rest of it ...'
BEST BATTERY EVER: All lithium, all the time, plus a dash of carbon nano-stuff
We have found the Holy Grail (of batteries) - boffins
Asteroid's DINO KILLING SPREE just bad luck – boffins
Sauricide WASN'T inevitable, reckon scientists
Flamewars in SPAAACE: cooler fires hint at energy efficiency
Experiment aboard ISS shows we should all chill out for cleaner engines
The Sun took a day off last week and made NO sunspots
Someone needs to get that lazy star cooking again before things get cold around here
Boffins discuss AI space program at hush-hush IARPA confab
IBM, MIT, plenty of others invited to fill Uncle Sam's spy toolchest, but where's Google?
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
Securing Web Applications Made Simple and Scalable
Learn how automated security testing can provide a simple and scalable way to protect your web applications.