Saturday, 3 January 2015

Elephant No. 92: Devin's Hair Clip

Knowing how much I like elephants, my niece Devin asked her Mom to take a picture of her cute hair clip and send it to me. My first thought was that I should try to make something similar—I even bought all the materials. Then I decided that this elephant was perfect as it was, perched on the head of a pretty little girl.

Devin and her perfect hair clip.
Photo: Alison Robb

Elephant Lore of the Day
Although elephants appear to be bald creatures whose only hair is a smal wisp at the ends of their tails, elephants are actually covered with short, coarse hairs. Baby elephants are particularly hairy at birth, although much of that hair eventually falls out.

Those of us who live in cold climates tend to think of hair and fur as insulators against the cold: the thicker the hair or fur, the warmer the animal. In October 2012, however, scientist Elie Bou-Zeid and a team of researchers from Princeton University discovered that elephant hair actually serves a very different purpose. Instead of keeping the elephant warm, hair actually wicks heat away, helping to cool the animal.

Hair on the back of an African elephant's head (left) and an Asian
elephant's head (right).
Photo: Conor Myhrvold

Elephants—which generally live in the hottest parts of the world—have many ways of regulating body temperature. The many veins in their ears vent heat, which is partly why elephants flap their ears. They also have various points on their bodies which release body heat into the air. They spray themselves with water, hang out in shady areas, and cover themselves in mud. Hair as a cooling mechanism, however, was something entirely new.

The team discovered that heat from an elephant's skin is transferred to the base of the hairs. The heat is then conducted up the hair to the tip, where it dissipates. A similar effect has been observed on some plants, such as cacti.

The deciding factor is apparently the density of the hair. Elephants average only one hair per square inch, whereas humans average 1,290 hairs per square inch. More hair means more insulation, and less hair helps cool things off. This has more to do with the properties of hair, and less to do with the cooling effects of air blowing across a relatively hairless surface. For more on this story, please click here.

Baby Asian elephants are quite furry at birth. This six-week-old elephant
will lose much of her furry coat by the age of three, although she
will have some hair throughout her life. Asian elephants tend
to be hairier than African elephants.
Photo: David Caird

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