# Why did we develop sweat glands? **URL:** \ **Category:** Great Debates\ **Created:** [August 6, 2013, 3:12am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466 "2013-08-06T03:12:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Werekoala](https://avatars.discourse-cdn.com/v4/letter/w/7993a0/32.png) [@Werekoala](https://boards.straightdope.com/u/Werekoala)\ **Post date:** [August 6, 2013, 3:12am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/1 "2013-08-06T03:12:25Z")
Ok, I’m not a creationist, nor an irreducible complexist (is that a word?) but I did think about this earlier today as I sweltered in the Texas heat. How/why did we develop sweat glands? Traditional evolutionary biology states that over a given period of time, mutations that were conducive to survival bred true and lead to species-wide adaptations that carried on from generation to generation. However, this took a loooong time. So, we evolve from fish, to amphibians. They probably didn’t need sweat glands. Then we get dinosaurs who were, by all accounts, near-lizards. No sweat glands. Simultaneously (or near enough), hairy, small critters evolved. Leaving aside hair/sebaceous glands, how/why did extruding moisture from those glands end up become a response to trying to shed excess heat? In other words - how did enough of our ancestors who piddled out of their hair folicles survive to ensure that no matter what I do, I can’t avoid nasty pit-stains in my shirts for about 6 months of the year? How did any of them survive long enough to make that a survival trait? ---
**Author:** ![smiling\_bandit](https://avatars.discourse-cdn.com/v4/letter/s/e9a140/32.png) [@smiling\_bandit](https://boards.straightdope.com/u/smiling_bandit)\ **Post date:** [August 6, 2013, 3:34am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/2 "2013-08-06T03:34:13Z")
I understand there’s still considerable debate on that very topic. In an evolutionary perspective, proto-humans changed drastically and in a rather short period of time. Developing heavy use of sweat glands was one such change. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [August 6, 2013, 3:57am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/3 "2013-08-06T03:57:46Z")
> [@](#): > > How/why did we develop sweat glands? Why? As a means of providing for thermal cooling. How? As a mutation that, in the right circumstances gave proto-mammals an evolutionary edge. You could similarly ask why we have fur/hair…or myriad other aspects of modern biology. > [@](#): > > So, we evolve from fish, to amphibians. They probably didn’t need sweat glands. They didn’t need hair or fur either…and we seem to have lost the fins and tails as well. Why? Mutation and evolutionary advantage in shifting environments, such as in the air and on dry land (they wouldn’t need or be able to use sweat glands in the water, so if they had such a mutation or even the gene for a proto-sweat gland it would have given them no advantage UNTIL they left the water). > [@](#): > > Then we get dinosaurs who were, by all accounts, near-lizards. No sweat glands. Dinosaurs weren’t lizards or even of the lizard family…more like birds. They had other means of cooling themselves, and regardless, we aren’t descended from most ‘dinosaur’ species since mammals split off from them somewhere between 200 and 80 million years ago. > [@](#): > > Simultaneously (or near enough), hairy, small critters evolved. Leaving aside hair/sebaceous glands, how/why did extruding moisture from those glands end up become a response to trying to shed excess heat? I doubt there is a firm answer to this one, but we have a lot of folks well schooled in evolution on this board so I’ll let them answer if there is a specific answer. My WAG is that it was a mutation sometime in an earlier species that became an advantage (or, initially not a huge disadvantage) that eventually gave our ancestor species an edge when the climate shifted or when a lot of ecological niches opened up during one of large extinction events (such as the Chicxulub impact). > [@](#): > > In other words - how did enough of our ancestors who piddled out of their hair folicles survive to ensure that no matter what I do, I can’t avoid nasty pit-stains in my shirts for about 6 months of the year? How did any of them survive long enough to make that a survival trait? Shedding heat in this way obviously gave our ancestor species an advantage. And later those sweat glands gave rise to those large breasts that many men love so much. 😉 ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 6, 2013, 4:14am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/4 "2013-08-06T04:14:59Z")
Other mammals have sweat glands, though they aren’t as effective at cooling and may not be as plentiful as in humans. But the genes for sweat glands were there before humans were, so what evolved was possibly an increase in the number of sweat glands, and of a more effective type. The changes may be associated with our loss of thick fur. Thick wet fur may not be an effective system of cooling. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [August 6, 2013, 4:37am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/5 "2013-08-06T04:37:50Z")
> [@XT](#): > > Dinosaurs weren’t lizards or even of the lizard family…more like birds. They had other means of cooling themselves, and regardless, we aren’t descended from most ‘dinosaur’ species since mammals split off from them somewhere between 200 and 80 million years ago. Actually, proto-mammals split from proto-reptiles between 300 and 320 million years ago, long before the dinosaurs. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [August 6, 2013, 4:42am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/6 "2013-08-06T04:42:48Z")
I doubt whether sweat glands fossilize very well, so direct evidence is likely to be hard to come by. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [August 6, 2013, 4:46am UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/7 "2013-08-06T04:46:22Z")
> [@XT](#): > > Shedding heat in this way obviously gave our ancestor species an advantage. And later those sweat glands gave rise to those large breasts that many men love so much. 😉 OK, I’m in. ---
**Author:** ![theR](https://avatars.discourse-cdn.com/v4/letter/t/977dab/32.png) [@theR](https://boards.straightdope.com/u/theR)\ **Post date:** [August 6, 2013, 12:45pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/8 "2013-08-06T12:45:35Z")
> [@TriPolar](#): > > Other mammals have sweat glands, though they aren’t as effective at cooling and may not be as plentiful as in humans. But the genes for sweat glands were there before humans were, so what evolved was possibly an increase in the number of sweat glands, and of a more effective type. A perfect example of animals with sweat glands that most people think of as not having them are dogs. They have two different types, including apocrine glands that release sweat into hair follicles, possibly for pheromones. They also have sweat glands around the pads on their paws and their noses. It’s not their primary cooling method but they do sweat through their foot pads. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [August 6, 2013, 12:48pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/9 "2013-08-06T12:48:52Z")
> [@XT](#): > > Why? As a means of providing for thermal cooling. And to attract women. Just ask Rasputin. Well, you could ask him, but he’s dead. ---
**Author:** ![BrokenBriton](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@BrokenBriton](https://boards.straightdope.com/u/BrokenBriton)\ **Post date:** [August 6, 2013, 12:51pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/10 "2013-08-06T12:51:41Z")
Every serious cardio session we do as a group I can’t believe the difference between men and women on this. Men have literally pools under them and the women nothing - and there is no way the women work less hard. It’s an extraordinary differential. Similarly with that ‘steam’ thing that, when you catch the sunlight, you can see eminating from men. Not a damn thing from the women. I have no idea what’s happening. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [August 6, 2013, 1:18pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/11 "2013-08-06T13:18:25Z")
I’m not evolutionary biologist, but it is interesting to note that humans, unlike almost any other land-dwelling mammal I can think of, are constructed for endurance, not speed. As the old saying goes, a cheetah will always catch a man, and a man will always catch a cheetah. Predators like lions, wolves and bears are designed for short bursts of immense expenditure of energy, followed by eating a rest. We aren’t; our advantages lie not in speed and strength but in running animals into the ground. While a lion’s logical approach to cooling off would be finding a cool place to lie down after a few minutes of effort, a human has to have some sort of cooling system that can kick in while s/he is still hunting. That might explain our sweatiness. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [August 6, 2013, 1:29pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/12 "2013-08-06T13:29:09Z")
> [@BrokenBriton](#): > > Every serious cardio session we do as a group I can’t believe the difference between men and women on this. Men have literally pools under them and the women nothing - and there is no way the women work less hard. It’s an extraordinary differential. > > Similarly with that ‘steam’ thing that, when you catch the sunlight, you can see eminating from men. Not a damn thing from the women. > > I have no idea what’s happening. Is this confirmed somewhere, that women sweat less than men? I’ve never noticed anything like that. And a ‘steam thing emanating from men?’ Do others know about this? ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [August 6, 2013, 1:30pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/13 "2013-08-06T13:30:12Z")
> [@theR](#): > > A perfect example of animals with sweat glands that most people think of as not having them are dogs. They have two different types, including apocrine glands that release sweat into hair follicles, possibly for pheromones. > > They also have sweat glands around the pads on their paws and their noses. It’s not their primary cooling method but they do sweat through their foot pads. People think of dogs as not having sweat glands? 😕 Have they never smelled a dog after it’s been running around a while? ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [August 6, 2013, 2:06pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/14 "2013-08-06T14:06:10Z")
> [@Frylock](#): > > People think of dogs as not having sweat glands? 😕 > > Have they never smelled a dog after it’s been running around a while? The “factoid” that dogs “sweat” through their tongues has transformed into “dogs ‘sweat’ ONLY through their tongues” with time and misremembering. There’s an unspoken assumption “therefore they have no sweat glands” that’s developed along with that. ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [August 6, 2013, 2:17pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/15 "2013-08-06T14:17:45Z")
Besides, fish secrete a film on their scales and amphibians have moist skin due to mucus glands so it’s not unreasonable to suppose that the solution simply evolved within the Tetrapod superclass. ---
**Author:** ![Werekoala](https://avatars.discourse-cdn.com/v4/letter/w/7993a0/32.png) [@Werekoala](https://boards.straightdope.com/u/Werekoala)\ **Post date:** [August 6, 2013, 2:47pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/16 "2013-08-06T14:47:59Z")
> [@Jackmannii](#): > > And to attract women. Just ask Rasputin. Well, you could ask him, but he’s dead. Is he? IS HE? … ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [August 6, 2013, 2:56pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/17 "2013-08-06T14:56:18Z")
> [@Werekoala](#): > > Traditional evolutionary biology states that over a given period of time, mutations that were conducive to survival bred true and lead to species-wide adaptations that carried on from generation to generation. However, this took a loooong time. Evolution doesn’t necessarily require vast periods of time. Since 1972, the Punctuated Equilibrium model has offered an alternative to gradualism: extremely rapid change into a new species, followed by long periods of (relative) stasis in that form. This theory does a good job of explaining what we see in the fossil record: identical-looking species for long periods (even millions of years), followed abruptly by different- (sometimes _very_ different)-looking animals. I’m not up on the latest in paleontology, but Punctuated Equilibrium has always sounded solid to me. ---
**Author:** ![BrokenBriton](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@BrokenBriton](https://boards.straightdope.com/u/BrokenBriton)\ **Post date:** [August 6, 2013, 3:00pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/18 "2013-08-06T15:00:31Z")
> [@Frylock](#): > > Is this confirmed somewhere, that women sweat less than men? I’ve never noticed anything like that. And a ‘steam thing emanating from men?’ Do others know about this? You’ve never seen this? > **[rugby steam - Google Search](https://www.google.co.uk/search?safe=off&hl=en&authuser=0&biw=1280&bih=630&site=imghp&tbm=isch&sa=1&q=rugby%2Bsteam&oq=rugby%2Bsteam&gs_l=img.12..0i10i24j0i24l2.21549.23806.0.26177.4.4.0.0.0.0.99.388.4.4.0....0...1c.1.24.img..0.4.386.MKYX5a1HTdE)** As for men vs. women: > [@](#): > > What they found: Although both men and women drank the same amount of fluid, women’s sweat rate was 0.57 liters per hour compared to the much higher 1.12 liters per hour sweat rate of men in the study > **[Why do men sweat more than women?](https://health.howstuffworks.com/wellness/men/sweating-odor/men-sweat-more-than-women.htm)** > > You know the cliché: Men sweat, but women perspire. You've seen both men and women sweating at the gym and know the cliché's true. But a sweat gland is a sweat gland -- whether it's from a male or female body. So why do men sweat more than women? ---
**Author:** ![Tamerlane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tamerlane/32/7602_2.png) [@Tamerlane](https://boards.straightdope.com/u/Tamerlane)\ **Post date:** [August 6, 2013, 4:16pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/19 "2013-08-06T16:16:43Z")
Pedantry… > [@RickJay](#): > > Predators like lions, wolves and bears are designed for short bursts of immense expenditure of energy, followed by eating a rest. Lions and bears are designed for short bursts. But wolves are endurance hunters like ourselves and one of a handful of species capable of giving us a good run for our money, as it were. Otherwise I think you are on the right track. Our massive profusion of eccrine sweat glands relative to other mammals is surely tied into our development into an apex endurance predator. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [August 6, 2013, 4:40pm UTC](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466/20 "2013-08-06T16:40:37Z")
> [@BrokenBriton](#): > > You’ve never seen this? > [rugby steam - Google Search](https://www.google.co.uk/search?safe=off&hl=en&authuser=0&biw=1280&bih=630&site=imghp&tbm=isch&sa=1&q=rugby+steam&oq=rugby+steam&gs_l=img.12..0i10i24j0i24l2.21549.23806.0.26177.4.4.0.0.0.0.99.388.4.4.0....0...1c.1.24.img..0.4.386.MKYX5a1HTdE) Of course not, or I would not have asked the question. > [@](#): > > [Why do men sweat more than women? | HowStuffWorks](http://health.howstuffworks.com/wellness/men/sweating-odor/men-sweat-more-than-women.htm) Thanks for that information. [Next page](https://boards.straightdope.com/t/why-did-we-develop-sweat-glands/665466.md?page=2)