Scientists solve jumbo mystery

GERMAN ZOO: Both little African elephants, Shavu and Uli, share the same father, Tusker, who comes from SA. Picture: AP

GERMAN ZOO: Both little African elephants, Shavu and Uli, share the same father, Tusker, who comes from SA. Picture: AP

Published Oct 18, 2012

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Johannesburg - For 300 years, scientists have pondered an evolutionary riddle: why is it that elephants have hair?

The bristly hairs that cover the world’s largest mammal are too few to keep it warm – and besides, who needs warmth in Africa and Asia? Could it be that the hair on an elephant has no purpose whatsoever?

Now three scientists believe they have the answer.

The elephant’s thin coat of hair is not there to keep it warm, it is there to cool it down.

The scientists from Princeton university came to this conclusion after a three-year study that included examining close-up photographs of tame African elephants in Botswana, computer programs and mathematical formulae.

What they found is that the sparse covering of hair helps an elephant to “dump heat”.

These hairs are so effective that they can enhance heat loss by between five and 20 percent, depending on wind speed, the study found.

Heat from the skin dissipates through each hair, explained Conor Myhrvold, one of the authors of the paper that appeared in the journal Plos One.

Air brushing past these single hairs works like heat-gathering highways, he explained.

Elephants use other mechanisms to lose heat, like flapping their ears as fans and drinking as much as 200 litres of water a day.

Myhrvold and his colleagues found that as the density of the hair increased, the amount of heat loss decreased.

Interestingly, a very close relative of the elephant used hair in a different role.

“Woolly mammoth and elephant hair were found to be almost identical,” said Myhrvold.

Elephant hair was first described in 1712 by Antonie van Leeuwenhoek, the inventor of the modern microscope. At the time, he wondered what the purpose of elephant hair was.

The research might help explain the scarcity of hair on another animal species – humans.

A new school of research, led by scientists like University of Utah biologist Dennis Bramble and Harvard University palaeoanthropologist Daniel Lieberman, suggests that early humans needed rapid cooling systems like sweat glands and now, perhaps, hair.

“This is definitely worth investigating,” Myhrvold said.

Using hair to dump heat, he believes, would make sense.

Myhrvold won’t be looking at humans. He plans to continue studying elephants, in particular looking at how hair density changes between different population groups. - The Star

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