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Sweating may be why we became the dominant species on Earth
While today profuse sweating is a social embarrassment, in the past it gave us an evolutionary advantage.
Persistence truly does pay off, even if you have to endure the perspiration that comes with it. This is true right down to the biological and evolutionary level, and is in fact how we got here, as the apex predator of the planet. Millions of years ago, digestion consumed most of the calories we ate. These days, our brain takes 20 times more energy than any other organ in the body. So for our brain to develop, we needed a higher density food. Meat—obtained from hunting and killing other animals—fit the bill.
One theory of human evolution states that our ancestors began eating meat about 2 million years ago, which rapidly expanded the development of their brains. Since meat packed a lot of calories and fat, a meat-based diet allowed the brain to grow larger. But how did early humans get that meat?
One way was eating carcasses, just like pack animals of today still do. The human tapeworm evolved from the kind that infects dogs and hyenas, which means that at some point, we must’ve fed on the same carcasses as them, and came into contact with their saliva. But this wasn’t the only way we obtained meat.
Ancient hominids must’ve fed on carcasses much like wild dogs and hyenas, before moving on to hunting. Wild African Dogs consuming a blue wildebeest. Credit: by Masteraah, Madikwe Game Reserve, South Africa.
Early humans must’ve taken part in hunting too. Yet, hominins didn’t begin using stones and sticks for hunting until about 200,000 years ago. So between 2.3 million and 200,000 years ago, how did early humans hunt? According to journalist and writer Christopher McDougall, author of the book Born to Run, we ran game animals to death in order to feast upon them.
The ability to run long distances and sweat—so as not to overheat, allowed our ancestors to wear out other animals. Sweating was the key factor. Consider a gazelle running over long distances and being chased by our progenitors. The fact that they can sweat and the gazelle can’t means they can last far longer in the heat of the African Savannah.
Game animals like the gazelle over time become overheated and have to stop to catch their breath, allowing early hunters to make short work of them, a strategy we call today persistence hunting. After about five miles or so, a gazelle needs to stop, rest, and breathe, or risk damaging itself, even dying. Such an animal can only fully extend its diaphragm when not running, while walking upright freed our ancestors from such an issue.
Human sweat is actually a very efficient cooling system, arguably the most effective in the animal kingdom.
Sweating may also act as a defense mechanism. Credit: Getty Images.
Research shows that several traits simultaneously evolved around the same time, about 1.89 million years ago. These were walking upright, hairless skin, sweating, and the ability to run great distances. One reason for all of these rapid changes might have been climate change. The Earth warmed over this same period, shifting the habitat from forest to open grassland, and allowing our ancestors to walk upright and even run in open space. It may have also forced them to hunt animals for food.
Sweating, in addition to being a highly advanced cooling system, may have also acted as a defense mechanism. Anyone who’s ever played shirtless tackle football in the summertime knows how hard it is to catch someone who’s slick and sweaty. So the next time you’re sweating bullets in some social situation, take a moment to calmly reflect on the fact that despite the awkwardness of your perspiration, this biological function is the main reason why you’re able to suffer such indignities in the first place.
To learn more about the science behind sweating, watch this:
Sallie Krawcheck and Bob Kulhan will be talking money, jobs, and how the pandemic will disproportionally affect women's finances.
Men take longer to clear COVID-19 from their systems; a male-only coronavirus repository may be why.
- A new study found that women clear coronavirus from their systems much faster than men.
- The researchers hypothesize that high concentrations of ACE2-expressing cells in the testes may store more coronavirus.
- There are many confounding factors to this mystery—some genetic, others social and behavioral.
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A laboratory technician at Queen Elizabeth University Hospital, Glasgow, holds a container of test-tube samples from people tested for novel coronavirus.
Further research required<div class="rm-shortcode" data-media_id="z9vH49bb" data-player_id="FvQKszTI" data-rm-shortcode-id="7ef1ab8ca2f90b28543d580c408ed25f"> <div id="botr_z9vH49bb_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/z9vH49bb-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/z9vH49bb-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/z9vH49bb-FvQKszTI.js"></script> </div> <p>The Montefiore-Einstein study is currently preliminary, and further research will be required before researchers can determine what, if anything, its results illuminate.</p><p>The study is currently published on <em>Medrxiv</em>, a <a href="https://www.aje.com/arc/benefits-of-preprints-for-researchers/" target="_blank">preprint</a> distributor. This means the study has been shared publicly before undergoing the <a href="https://undsci.berkeley.edu/article/howscienceworks_16" target="_blank">peer-review process</a>.</p><p>Preprints allow researchers to communicate their findings before official publication, which can take months if not a year or longer. This pre-publication can lead to early feedback, increased visibility, and new collaborations. It's especially helpful for <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6400415/" target="_blank">early-career researchers</a> trying to establish themselves.</p><p>However, given the speed at which coronavirus is spreading, researchers have leaned on preprints as a means of disseminating data to other experts faster than the peer review allows. As a result, <em>Medrixiv</em> has seen a <a href="https://www.nytimes.com/2020/04/14/science/coronavirus-disinformation.html" target="_blank">surge of preprint studies</a>, but they must be read within the context of their preliminary status.</p><p>The Montefiore-Einstein also has its limitations. The study had an initial sample size of only 68 subjects (48 males, 20 females) and a further examination of three families. And the connection of coronavirus to ACE2 enzymes in the testes came from database research, not direct observation.</p><p>The researchers acknowledge the need for further investigation. In particular, Shastri stresses the need to confirm the coronavirus's ability to infect and multiply in testicular tissue. If other researchers find their data promising, they could move forward with new research to build upon the study and see if this clue fits into the mystery.</p>
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Coronavirus protesters in Los Angeles. Men are more likely than women to disregard health warnings from officials.
The word "learning" opens up space for more people, places, and ideas.
- The terms 'education' and 'learning' are often used interchangeably, but there is a cultural connotation to the former that can be limiting. Education naturally links to schooling, which is only one form of learning.
- Gregg Behr, founder and co-chair of Remake Learning, believes that this small word shift opens up the possibilities in terms of how and where learning can happen. It also becomes a more inclusive practice, welcoming in a larger, more diverse group of thinkers.
- Post-COVID, the way we think about what learning looks like will inevitably change, so it's crucial to adjust and begin building the necessary support systems today.
The coronavirus pandemic has brought out the perception of selfishness among many.
- Selfish behavior has been analyzed by philosophers and psychologists for centuries.
- New research shows people may be wired for altruistic behavior and get more benefits from it.
- Crisis times tend to increase self-centered acts.