Do Shark sweat? They eat a lot of salty food.
Did Sweating Evolve To Keep Us Cool Or Expell Excess Salt?
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Do Shark sweat? They eat a lot of salty food.
Is that the best you can do? It's the mammals that were interested in. The scenario I envisage does seem to fit, the sea breeze would be an effective environment for sweating to be a beneficial cooling mechanism. Humid, dry or cold conditions don't suit heavy sweating. What other mammals other than humans and horses have this specialist cooling mechanism??
Your idea? :bugeye: You are quite clearly parroting the Aquatic Ape Hypothesis. Why are you being so coy about it and dancing around to avoid using the phrase? Why not just come right out and say it?
There are not many people on internet science forums who you could fool into thinking that it’s your hypothesis. It's practically an internet meme. And as for it being a "good idea", well that's highly debatable. The "evidence" is riddled with selective misinterpretation. The consensus amongst actual evolutionary scientists is that it’s bunk.
It's a valid question, and seemingly one you can't answer easily, so I can tell it rather defeats you argument.
And sharks.
Cats and dogs pant, and sweat through the pads on their feet. They do this when they are HOT, not salty!
I thought of it independently, believe it or not. I haven't read anything about the Aquatic Ape Theory. Is it connected to the Congo Estuary or to the Congo basin? The fact remains that a sea breeze coastal environment is the only habitat which suits heavy sweating as a cooling mechanism, especially since a high fresh water intake is essential. It's common sense surely?
Fraggle Rocker
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Only mammals have sweat glands. None of the other orders of chordates have them. BTW, mammary glands are modified sweat glands. We got to be mammals in the first place because we sweat.
Almost all mammals have sweat glands, although in many species they are reduced to only being present on their feet. I believe the only mammals that don't have them are the cetaceans, because they are the only ones who have become completely aquatic.
Other mammals have different ways of cooling. Dogs open their mouths and let saliva evaporate off of their tongues, but it's less commonly understood that the reason they have wet noses is also for evaporative cooling.
The drier the air, the more efficient the cooling effects of sweating.
Sea breezes are not particularly dry. Fresh water sources are not really that prevalent near the ocean.
A reasonably well conditioned human being can jog ten miles in an hour or so over dry grassland without drinking water - sweating all the way.
People develop their sweat glands over the first 30 months of their life; people born in tropical countries, such as India or Ghana for instance, have more than those people who grow up in colder, less humid countries. Hence the problem of prickly heat suffered by the English when they were in India or Africa--they didn't have enough sweat glands to cope adequately with the humidity and heat of the tropical environments.
So Eskimos sweat, to keep their skin lubricated, do they? I should think they go to great lengths to make clothing that allows moisture to exit, to prevent sweating, actually.
Exactly why I posed the question, ... the relevance of which seems to have passed by the OP.
Fresh water is certainly easier to find on the coast - stream and river outlets! I'm an excessive sweater who's travelled the world and I can tell you that the coast is the only place where it feels natural in a hot climate. You can also cool off by swimming in the sea and cool down via the sea breeze. Anywhere else is a pain. Can we come to an agreement that profuse sweating is a poor cooling mechanism in DRY, HUMID and COLD conditions. My proposal does make sense. There's always a combination of factors in a bodies ability to keep cool, and profuse sweating is one of them which will be phased out in my opinion.
sweat doesn't have to evaporate to lower ur temperature, u wipe it off, it drips off, it gets in ur hair, it gathers on anything you brush past. so climate might not be that important.
what part of the body measures salt levels in the body? can u connect it to the sweat glands?
what part of the body measures salt levels in the body? can u connect it to the sweat glands?
It exactly DOES have to do that! How do you think it works otherwise?
Fraggle Rocker
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Yes it does. That's the cooling mechanism. The transition of one gram of water from liquid state to gaseous state extracts 100 calories (small c: that's 1/1000 of a large c Calorie in your candy bar, which is really a kilocalorie) from the surrounding matter. That's 100 times as much heat energy as it takes to simply raise the temperature of one gram of solid, liquid or gaseous water by one degree. So if one gram of water evaporates from your skin, it sucks enough heat out of your skin to lower the temperature of 100 grams of skin by one degree. That's a really efficient process.
does the sweat carry heat away from the body without evaporating?
Fraggle Rocker
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I suppose from sheer thermodynamics it might carry a minute amount, if there were a high wind blowing and it cooled down the surface area of the water droplets because they were sticking out into the windstream at just the right angle. But it would be two orders of magnitude less than the heat the sweat seizes by evaporation, so it would not have a substantive effect on comfort.
That would be a difficult experiment to set up because there'd be no way to stop the water from evaporating. I suppose you could slather your body with another liquid that isn't as volatile as water and see how it feels, but it would have to be something as harmless as water.
The kidneys can condense and excrete a massive amount of salt. cup your hand and fill it with salt and that's about the amount your kidneys can excrete efficiently PER DAY.
Sweat is for cooling and probably for coating the skin in wax (many African's tell me they get a bit of waxy buildup and that's why some can't shave well - it kind of clogs up the pours) and it may have some pheromone properties. But one thing sweat does NOT do well is excrete salt!
Sweat is for cooling and probably for coating the skin in wax (many African's tell me they get a bit of waxy buildup and that's why some can't shave well - it kind of clogs up the pours) and it may have some pheromone properties. But one thing sweat does NOT do well is excrete salt!
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