- Researchers discover a new feature of human evolution.
- People have come to use less water per day than other prime ministers.
- The nose is one of the factors that allows people to be water efficient.
Scientists have discovered a new feature that makes humans different from other primates like chimpanzees. The research shows that the human body uses 30% to 50% less water per day than our closest relatives.
Sure, our brain power, and the ability to walk directly are crucial in making us special but the efficiency with which the human body uses water is another key difference. This feature seems to have originated as an evolutionary change in older hunter-gatherers, who had to go further and further away from water sources in search of food, the lead author of the study believes Herman Pontzer, associate professor of evolutionary anthropology at Duke University.
“Even being able to go a little further without water would have been a huge benefit as early people started making a living in dry, savannah landscapes,” Pontzer said.
Since our body is constantly getting rid of water through processes such as moistening or taking a shower, water levels need to be restored. “To sustain life, humans and other terrestrial animals must maintain a tight balance between water gain and daily water loss,” the paper’s authors write.
For the study, the researchers looked at this cycle of water consumption and loss in 309 people from a variety of conditions. These included farmers, hunter-gatherers, and office workers, who compared 72 onions scattered around zoos and sanctuaries.
A model of water conversion for humans and chimpanzees with lean mass and body water baths.
Credit: Conventional Biology
The scientists measured the amount of water in each person in the study, whether it came from drinks or food. They also monitored the amount of water lost through urine, sweat or the GI system. With all the numbers added up, it became clear that the average person’s body goes through about 3 liters of water per day. That’s about 12 cups. A chimp or gorilla goes through twice as much.
The results were amazing because people tend to sweat more than other prime ministers. In one square inch of skin, “humans have 10 times as much sweat glands as chimpanzees do,” Pontzer explained. We can sweat out about half a gallon in a 30-minute workout. We also lead a much more active life than the apes at the zoo, with most lizards moving just once or twice a day, according to the scientists. So how do we use up less water?
The researchers believe that the real difference in water treatment observed in humans compared to other primates is related to evolutionary methods. Our bodies had to change so that they needed less water to stay healthy.
The scientists are now aiming to find out how this change happened. The data show that our thirst sensing was changing from other ape relatives. We just don’t want as much water. Notably, the water-to-calorie ratio is 25% lower in human breast milk than in ape milk.
It is also possible that our nose has a lot to do with this. Fossils indicate that humans began to acquire more protruding noses than its evolutionary cousins about 1.6 million years ago, with the breakdown of Homo erectus. In contrast, gorillas and chimp have flatter noses.
What’s good about our noses? As we tend to take out a lump of water, the nasal passages cool and condense to it, turning it back into liquid. This liquid accumulates inside the nose and gets repositioned back into the body. In fact, having a stuffy nose may have helped older people retain more moisture when breathing.
Read the study published in Conventional Biology.