Surprisingly Humans Use Less Water Than Our Animal Cousins

Our bodies are constantly losing water: when we sweat, go to the bathroom, even when we breathe. That water needs to be replenished to keep blood volume and other body fluids within normal ranges.

And yet, research published March 5 in the journal Current Biology shows that the human body uses 30% to 50% less water per day than our closest animal cousins. In other words, among primates, humans evolved to be the low-flow model.


Despite all the exhortations to stay hydrated, maybe that is why I drink water like it is poison.

As a long-distance runner, I’m grateful for this. I have to drink enough water as it is!


That is not surprising at all, given our current understanding of the selective pressures that produced us.

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I appreciate that. I’m a little afraid of it while morning sickness lingers. With my first pregnancy, it would induce immediate vomiting so I guess my body did treat it as poison. Gatorade kept me out of the hospital. It felt great to be able to drink water later. Now I can’t stand the thought of sipping and either gulp a whole glass or drink nothing.

Hydration is still good for you!

I wonder if we use less than most animals?

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I wrote the title that way because that’s what was described in the article by the scientist:

Pontzer says the researchers were surprised by the results because, among primates, humans have an amazing ability to sweat. Per square inch of skin, “humans have 10 times as many sweat glands as chimpanzees do,” Pontzer said. That makes it possible for a person to sweat more than half a gallon during an hour-long workout – equivalent to two Big Gulps from a 7-Eleven.

Add to that the fact that the great apes – chimpanzees, bonobos, gorillas and orangutans – live lazy lives. “Most apes spend 10 to 12 hours a day resting or feeding, and then they sleep for 10 hours. They really only move a couple hours a day,” Pontzer said.

I was thinking that only using animals in zoos would skew their results but then I read that paragraph. I suppose if behavior is the same in the wild and they also used sedentary humans for the research, it wouldn’t matter.

I venture to say that both Austrialipithus and early Genus Homo has similar traits that were diverged from the great apes. I venture to say that it was selective as we became a skilled hunter/gather. Can we say that it is a “human” characteristic"?

How can we know?

Plus the research is just comparing humans now to apes now. So I don’t think anything else can be extrapolated, except that this obviously requires significant evolution if we have a common ancestor.

But obviously I think it’s human trait. Just another way we are unique - we work, we sweat, and use water efficiently. Funny Genesis 3:19 came to mind as I was typing that previous sentence. Interesting symbolism of mercy in water. I like to think in metaphors. :relaxed:

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reminds me the (wierd) aquatic ape hypothesis:

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I thought these were some interesting details from another article I just read that I missed when I skimmed the paper.

Even among a small sample of adults in rural Ecuador, who drink a remarkable amount of water for cultural reasons (over 9 litres a day for men and nearly 5 litres a day for women), the overall water to energy ratio still matched humans elsewhere, roughly 1.5 millilitres for every calorie consumed.

In fact, it’s worth noting that this same ratio is apparent in human breast milk. The breast milk of apes, on the other hand, has a ratio of water to energy that is 25 percent lower.

It’s interesting that we drink the same ratio as we did when we were babies. Why there was every once a campaign against breast milk seems even more ridiculous.

I wonder how much water saving (if any) also occurred by our loss of a functional uricase.

Uric acid is converted into allantoin by uricase.

Uric acid requires less water to remove than urea, and presumably allantoin.

The pattern of pseudogenisation of uricase in primates matches that of our common descent.

Humans are some of the best joggers in the animal kingdom, and when you combine this with the ability to sweat it adds up to a lethal combination. Humans can actually chase animals to exhaustion (i.e. persistence hunting).

I am always cautious of just-so stories for adaptations, but the adaptations for jogging and sweating are pretty compelling.


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