How water efficiency helped hunter-gatherer humans nose ahead of primate rivals

‘Having a nose that sticks out more may have helped early humans retain more moisture with each breath’

HAVING big noses helped early humans compete with primate rivals by reducing water loss, a study suggests.

Water efficiency became a distinguishing feature that separates humans from chimpanzees and other apes, as well as having bigger brains and walking upright on two legs.

Now research has shown the human body uses 30 per cent to 50 per cent less water per day than that of chimpanzees and gorillas, which may have helped hunter-gatherers venture further from streams and watering holes in search of food. And the answer, according to scientists, could be in the nose.

Research leader Herman Pontzer, associate professor of evolutionary anthropology at Duke University in North Carolina, said: “Even just being able to go a little bit longer without water would have been a big advantage as early humans started making a living in dry, savannah landscapes.

“A possibility lies in fossil evidence that suggests about 1.6 million years ago, with the beginning of Homo erectus, humans started developing a more prominent nose.

“Our cousins, gorillas and chimpanzees, have much flatter noses but our nasal passages help conserve water by cooling and condensing the water vapour from exhaled air, turning it back into liquid on the inside of our nose where it can be reabsorbed. Having a nose that sticks out more may have helped early humans retain more moisture with each breath.”

The study compared the “water turnover” of 309 people with a range of lifestyles, from farmers and huntergatherers to office workers, with that of 72 apes living in zoos and sanctuaries. For each individual the researchers calculated water intake via food and drink and water lost via sweat, urine and the GI tract, on the other.

When they added up all the inputs and outputs, they found that the average person processes some five pints (around three litres) or 12 cups of water each day.

A chimpanzee or gorilla living in a zoo goes through twice that much, scientists said. The research was published in the journal