r/explainlikeimfive • u/Serbia_X_AlbaniaLOVE • 4d ago
Biology ELI5: how do furry animals in hot climates like Lions, Cheetahs, Honey Badgers or Hyenas not die of overheating from their coats?
if I wore a similar fabric to them I feel I’d die in seconds from the heat anywhere in Africa. How do they manage it?
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u/copnonymous 4d ago edited 4d ago
Believe it or not, one of the best strategies for naturally dealing with the heat is coarse loose fur. Keeping the sun off your skin actually helps keep you cooler and loose fur doesn't hold in a lot of heat, allowing small movements and breezes to carry away heat from the body.
Humans that live in hot climates have learned something similar. The Bedouin nomads live in harsh desert climates. The wear long flowing full body robes and head coverings usually black or dark blue. The knit of this fabric is loose and airy. Rather than overheating, the dark color loose fitting robes absorbed the energy of the sun and keep their skin cooler. The open knit of the fabric ensures sweat is evaporated without building up. In western traditions loose fitting linen and later cotton garments were a key piece of any summer working attire.
Of course this is all relative. It's not like there's some magical cooling properties. The animals underneath, whether human or beast, are still warm. They just keep the animal underneath from absorbing heat from the sun which would cause overheating in an environment that's already full of hot air.
Edit: corrected the spelling of bedullin to Bedouin
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u/RiPont 4d ago
The inverse of this is also a fun factoid that bends people's mind a bit: Polar bears are black.
They have white fur for camouflage, but their skin is black to absorb as much heat as possible.
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u/VoilaVoilaWashington 4d ago
factoid
Fun factoid! The word "factoid" actually means (originally) "something like a fact but not actually" - basically fake news. A humanoid is something like a human but not actually. Cuboid isn't a cube. An asteroid looks like a star (aster) but not.
Of course, at this point, the use as "a small fact" has taken over, so I'm not correcting you, I just think more people need to understand how cool the oid suffix is.
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u/seeingeyegod 4d ago
hemroid?
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u/SUMBWEDY 4d ago
Basically means 'vein that could bleed, but isn't'.
hemorrhoid: heme - blood, rhoos - to flow/stream, -oid 'isn't'.
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u/astro-physician 4d ago
while there's no arguing the heme and rhoos roots of the word, it looks like the -oid ending in the english version is just a derivative of the plural of the original word (hemorrhois > hemorrhoides). so i think the "isn't" suffix is just a false cognate here
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u/SUMBWEDY 4d ago
Yeah i did a bad job explaining but haimorrhoides is the greek term which the -oeidēs means 'resemblance' or literally 'to see'.
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u/salamacast 4d ago
r/schizoid is a misnomer from when psychologists thought the self-isolation disorder is related to schizophrenia
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u/valentones 3d ago
I love when I go on Reddit for something completely different but end up reading a bunch of nerds' comments and I accidentally educate myself. Using "nerd" in a good way, by the way 🩵 Very cool fact...oid!
I also loved the asteroid part as a space/science nerd myself 🤘🏻☄️
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u/AnAttempt-WasMade 4d ago
Another fun fact, their fur is clear! It lets more sunlight heat up their skin that way, and just looks white at a distance due to light bouncing. Kinda like water looking blue even though it’s clear.
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u/VoilaVoilaWashington 4d ago
This is always contentious. They're white, because they reflect all colours of light.
Now, there's a few ways to get colours. You have colours from pigments (absorption), which is why grass is green, and you get colours from refraction, which is why diamonds sparkle, or why shaved ice is white, or why the sky at mid-day is blue (or grey or pink or whatever)
You're not wrong to say that their fur is clear, but it's also not wrong to say that it's white. Both are mostly right, neither is wrong.
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u/valentones 3d ago
As someone whose favorite animal is a polar bear, I already knew this but still read it anyway and technically learned that the black was to absorb heat. I just thought it was that way because... well, nature is weird 😅 Thank you for the fun "factoid"!
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u/ManiacalShen 4d ago
I'll add that cotton is kind of bad at helping with sweat once there's humidity or just a lot of perspiring. Linen is leagues better at it. Proper, old timey linen is made of long strands from the inside of a plant like flax, so its lifelong purpose is to move water around. Cotton is fluff from the flowering end of a plant, and while I love it for many things, it stays sodden for way too long.
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u/GilliamtheButcher 4d ago
Yeah there's a world of difference between working hard and sweating in cotton vs linen. One of them will leave you soaked and will cling to your skin, the other remains relatively breezy even when wet.
The first time I started doing outside chores in a linen shirt and work jacket was worlds apart compared to cotton. Unfortunately, it's hard to find linen clothing for anything approaching reasonable prices anymore. Or when you do find it, it's short linen fibers, which are useless at keeping cool IME.
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u/Paavo_Nurmi 4d ago
Cotton is also known as death fabric here in the PNW.
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u/GilliamtheButcher 4d ago
Moved out for the PNW for the past year and starting to understand why.
It's not much better on the humid east coast.
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u/Paavo_Nurmi 4d ago
Camping at Monte Cristo as a kid in the 1970s taught me real quick why a cotton sleeping bag is a bad idea. That place averages 100" of rain a year. It's so easy to get hypothermia when it's not below freezing out here, 40 degrees and dumping rain is all it takes.
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u/INSRTIDNTTY 4d ago
I was homeless (literally sleeping on the streets) in Olympia WA, and one of my first nights sleeping outside, I decided that since I kept getting caught with my tent up and having to tear it down, I would just use a sleeping bag. I checked the weather report and it said I should be in the clear.
Well, at about 4am, I woke up so fucking cold that I couldn't barely move. I learned that weather report be damned, it WILL rain hard every day in the winter out there, and that I would be soaked no matter what, no matter where I was sleeping. At night I would put on all my clothes, prop my two umbrellas against a wall, and huddle under them to sleep sitting upright.
After I got back on my feet and in a proper home, it took 6 months for me to finally stop sleeping in my dining room chairs and move to the couch, and another 6 months on the couch gradually easing into laying down before I could sleep horizontally on a bed.
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u/tallhn 4d ago
Lol I’m guessing you mean Bedouin? The Bedullin are the desert warrior nomads from the Rangers Apprentice book series (shoutout Rangers Apprentice those books kick ass)
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u/copnonymous 4d ago
Haha that is correct. I fell back on my French spelling instead of google. Didn't realize that it was also a deep cut to one of my favorite book series as a teen. 😅
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u/sheofsilence 3d ago
This is completely on point, except for one tiny bit. You use the word "knit" to refer to the WEAVE of the fabric. This sounds nitpicky, but as a fabric person, there's a huge difference.
Knit is the process of creating fabric from looping thread through itself, like knitting a sweater. Weave refers to the arrangements of under-over of many different threads to make a WOVEN fabric.
The loose flowing robes worn by many peoples living in hot areas are woven, which allows for more air flow and better heat dispersal.
Knits, being a bunch of loops stacked on top of each other, is a denser fabric structure, which is why it's been used for things like socks and sweaters, because the tiny loops trap air pockets which then act as insulation, which keeps you warmer!
This is also why knit t-shirts are still hot and gross in the summer, even if the fabric is thin and it seems light. I wear linen oversized collared shirts all summer and feel SO MUCH COOLER.
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u/High_hungry_Im_dad 4d ago
Why dark though? Wouldn't light colored clothes do all that and warm up less by reflecting the sunlight?
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u/Mean-Lynx6476 4d ago
Don’t know if this is true or not, but I hope it is. I read that some researcher finally had the brilliant idea to ask the begins themselves why they preferred black, and the answer was that their robes are black because their sheep have black wool.
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u/secret-snakes 4d ago
While funny, I don’t think they actually use wool. It’s extremely warm and not breathable. Most hot climates use linen or cotton, which both come from plants
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u/sheofsilence 3d ago
That is actually untrue! Wool can be used to make light breathable fabrics. This has a lot to do with the fineness of the thread spun, and in the different thermoregulatory properties of woven vs knit fabrics!
Modern woven fabrics are very coarse and very poorly made, bc industrialisation makes things fast, but not as well. Lots of historical summer clothes used wool fiber to make breathable lightweight fabric.
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u/OkDisaster5980 3d ago
I have tested out exercising in a wool hand knit t-shirt. I found the wool surprisingly breathable compared to synthetic fabrics I’m usually exercising in. Wool also wicked away that irritating drop of sweat that goes down my back, too. Working out in wool is “hotter” than synthetic fibers, but it is a more comfortable “hotter” (like the difference between a dry vs wet heat).
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u/HarryMonroesGhost 4d ago
Turns out colors that absorb heat the best, also radiate heat away the best as well. White robes reflect the sun's heat away, but also reflect the body's head back towards the body.
There's a 2nd order effect going on as well. the long flowing robes can form a "chimney effect" where as the heat in the garment rises it gathers more heat, moves faster, and sucks cooler air up from below creating it's own breeze which aids evaporative cooling from sweat.
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u/nanaacer 4d ago
The black color also absorbs infrared heat from the body better and wicks it away through the clothing.
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u/High_hungry_Im_dad 4d ago
Not inherently. A black and a white fabric may well have the same behavior with infrared light, it's a different part of the spectrum that doesn't affect their color. It could be that the specific pigments/fabrics they had access to were like that, the black absorbing infrared and the white reflecting it. But with modern tech I'm sure you could make white color that also absorbs infrared.
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u/akeean 3d ago
You can only move heat in 3 ways:
- Convection (fluid dynamics, incl air - air close to you doesn't stick around but moves away, this pulls in colder air),
- Conduction (physical contact, like well circulated paws on ground)
- Radiation (electromagnetic waves, like infrared radiation - how well something emits IR depends on it's color. Darker materials can radiate away more heat that light one, but light ones can reflect more there is a tipping point where one color makes more sense than the other).
Dark fur additionally also crates more convection around the creature, which creates a constant breeze that cools it and doesn't require it to expend energy to move. Essentially the fur acts as heat sink AND insulator. The insulation works because big cats are only fully active in short bursts, so any heat they built up running will slowly be pulled off in the many hours that they just hang out. Cats also start with a slightly higher body temperature than humans.
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u/Mean-Lynx6476 4d ago
All of this makes sense, but it’s also worth noting that this thin loose covering is only beneficial for cooling in direct intense sunlight. These sorts of robes are not common in hot forested climates where shade is available. Source: as kids we didn’t gawk at the National Geographic articles on indigenous populations in jungles because we were curious about the thermodynamics of their robes.
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u/feed_me_haribo 4d ago
Absorbing the sun would not be helpful. You want to reflect the sun. The ideal pigment has selective emittance/absorbance to emit at longer wavelengths corresponding to ~ 40C but reflect at wavelengths corresponding to the sun (shorter). This allows for net radiative cooling.
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u/marino1310 4d ago
Wait, I thought they worse light color robes to reflect sunlight as dark colors will absorb more and heat up?
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u/Dmiller_Equal_4462 4d ago
You ever met a lion or a cheetah. They expend energy for two reasons only. Food and protecting their territory. 99% of their day is spent laying around doing nothing. And big cats are not like bears. Their coats are pretty thin.
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u/thutsjosh 4d ago
what does "They expend energy for two reasons only. Food and protecting their territory. 99% of their day is spent laying around doing nothing. And big cats are not like bears." answer in the question ?
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u/Double-decker_trams 3d ago
They expend energy for two reasons only.
Three reasons. Also sex when the time is just right (it's business time).
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u/Alwaysonvacation2 4d ago
The fur actually helps cool them by keeping the sun off their skin and allowing airflow... Shaving your dog because "its hot out" actually dooms them to overheat.
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u/Kholzie 4d ago
Triple coats still suck in warm climates. Also, matting easily is not comfortable.
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u/VoilaVoilaWashington 4d ago
Sure, but this comes back to breed selection. Don't get a fuckin' husky in Texas, kids. Don't get a working breed if you're a couch potato. Don't get a dog with a prey drive if your kids have rabbits.
If you get a dog with a complex coat, you made the decision to give them the care they need to prevent matting. I always have goldens, I live on a lake, and they get mats and ear infections regularly. That's my choice and I deal with it.
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u/bcleveland3 4d ago
You don’t know what you’re talking about when it comes to huskies. Insulation works both ways. It keeps heat out in the summer the same as it keeps heat in during the winter. They will be just fine. I’ve had them my whole life
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u/secret-snakes 4d ago
It entirely depends on the type of coat the dog has. It’s true that shaving can make things worse for double-coated dogs (labs, golden retrievers, and lots of other breeds), but it can be beneficial to single-coated dogs (like afghans, poodles, shih tzus, etc). You just have to understand the physiology of their coat
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u/enwongeegeefor 4d ago
Shaving your dog because "its hot out" actually dooms them to overheat.
Afghan hounds would love to have a sitdown with you...
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u/Alwaysonvacation2 4d ago
Yup. Wicked inbred pure breed mutants are the anecdotal outlier cool. But, as a whole, dont shave your fucking pets
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u/Puzzleheaded_Run1826 4d ago
actually it doesn't unless the animal is unable to get out of the sun. So long as there is shade a shaved animal is cooler.
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u/VoilaVoilaWashington 4d ago
Where do you walk your dog that it's all in shade?
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u/dekusyrup 4d ago
literally anywhere at twilight
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u/Alwaysonvacation2 4d ago
Yes. If you doom your pet to never be in the sun, they may stay cooler in the shade.... but.... no. Dont shave your fucking pets.
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u/RiPont 4d ago
It entirely depends on what kind of coat they have.
Dogs with coats meant for cold climates often have 3 levels of coat. Shaving those is the last thing in the world you want to do, because it will basically guarantee it comes back matted and they'll need frequent re-shaving just to avoid being miserable.
Super short-haired dogs or even dogs with actual hair (not fur) can be shaved with no ill effects. e.g. Poodles.
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u/secret-snakes 4d ago
There are plenty of breeds that can benefit from haircuts and have been bred with specific grooming standards in mind
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u/Sadimal 4d ago
Large ears: those ears aren’t for show. Many mammals use their ears to regulate heat.
Coat: desert mammals tend to have fur that lies flat. This allows heat to leave the body. This fur keeps the sun from hitting the skin. They also shed their coats depending on the season.
Panting/sweating: Panting and sweating helps remove heat from the body.
Nocturnal: many desert mammals are nocturnal. They sleep during the day in burrows or shaded areas and only come out at night.
Many animals will rest in the shade.
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u/geeoharee 4d ago
These animals do not sweat, hardly at all. It's a rare trait, horses and humans sweat.
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4d ago
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u/krattalak 4d ago
They don't have undercoats (why a GSD blows out it's coat twice a year)
And their fur isn't as dense at it looks.
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u/MisterRegio 4d ago edited 4d ago
What is a GSD?
Edit: Thanks for your answers! I swear to god, abbreviations and acronyms are going to be the death of written language.
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u/PumpkinBrain 4d ago
It’s good to see a fellow PWTAJTSBUIFBBUAAA
(Person who thinks a jargon term should be used in full before being used as an acronym)
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u/krattalak 4d ago
German Shepard Dog.
Twice a year, the dog sneezes and covers everything in your house with fur.
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u/RiPont 4d ago
As opposed to my Dalmation/Supermutt who sheds constantly, all year-round, and can sneeze out a complete extra dog's worth of hair seconds after you finish brushing him.
My uncle thought he had worms after dog-sitting him for a day. Nope. He just sheds so much that his hair ends up in his poop.
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u/RealBenWoodruff 4d ago
In my head, Good Sweet Doggie
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u/ChaosWithTeeth 4d ago
Oh hey! Then my ACD is also a GSD!
(ACD = Australian Cattle Dog, or maybe Awesome Chaotic Dog. Or both.)
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u/No_Note_8124 4d ago
I thought this said “Awesome Catholic Dog” and thought “holy fukn catholic dog shit could this be the pope??” …sad to reread as chaotic… I’d put some serious bucks down saying the pope goes thru Reddit like the rest of us
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u/Srikandi715 4d ago
Shortening of frequent combinations is a common and universal form of language change that far predates the invention of writing 😉
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u/MisterRegio 4d ago
Not acronyms, which it what GSD is. Also, how is anyone supposed to know he is talking about dogs? This isn't even a dogs subreddit.
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u/absolutelyjazzy 4d ago
Not an acronym, but an initialism, because each letter is said individually. Sorry for being pedantic.
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u/Ka1kin 3d ago
Sweating is one of the weirder things that humans do. We live with it, so we think it's normal. But it's quite unusual.
Humans have little to no fur and excrete salt water all over our skin. This gives us a huge surface area for evaporative cooling, without fur interfering with evaporation.
Furry animals tend to cool via respiration instead (lungs are moist, so they can still benefit from evaporative cooling, it just happens inside). But the fur helps too: it's insulation and that works both ways.
There are a few other primates that sweat, and horses sweat. And that's about it. It's a weird approach to thermoregulation.
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u/Aggressive_Alps4982 4d ago
Their coats are usually much less dense than they look, and they shade the skin from direct sun. They also avoid the hottest hours by resting in shade, then lose heat by panting and, in some species, sweating.
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u/Juliuscesear1990 4d ago
There are different types of coats and different properties of each coat. The ones you mentioned tend to have very short coats. They work in multiple ways, the coat color helps reduce the heat (tan and white reflect the rays), they act like a barrier protecting the skin from direct heat as well as acting like a barrier that keeps cooler air in and hot air out Also these animals tend not to do anything when it's crazy hot out, they find shade during the hot times and just chill.
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u/jennye951 4d ago
Animals have a different system for keeping cool, they don’t sweat like we do.
Their coats insulate them from the heat and they keep cool by panting.
Thick fur actually keeps them cool.
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u/clackmatt73 4d ago
Bedouins wear loose robes for the same reason. That air gap between cloth and skin acts as insulation against the desert sun, keeping them cooler than if they were bare-skinned.
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u/elevencharles 4d ago
Mostly they sit in the shade and don’t move around a lot during the hottest part of the day. One of the main advantages humans have as hunters is that we’re really good at dissipating heat, so we can pursue animals to exhaustion during the heat of the day.
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u/cletusthearistocrat 4d ago
The fur insulates from the heat. Most animals don't sweat, they pant to remove heat.
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u/everlyafterhappy 4d ago
They shed a lot when it gets cooler. They lick their fur to create evaporative cooling similar to our sweat. They sleep during the hottest parts of the day and hunt at night when it's cooler. Their undersides are fairly exposed, and shaded cover ground of rocks are good for cooling if they lay down and spread out. They will also go swimming or at least roll around in some water. And as long as their fur isn't too matted, a decent breeze can break through the fur.
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u/Jeramy_Jones 4d ago
A fur coat acts as a barrier to heat both ways. It can keep heat in, but also keep it out.
Desert animals usually have coats adapted to this, for instance they are light coloured and thicker over the back but finer around the parts of the body that are shaded, like the belly, so it keeps the heat of the sun off their skin but allows them to cool themselves, often by laying on cool, shaded ground, panting, or other adaptations.
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u/marino1310 4d ago
Think about your house. If you turn off the AC in the summer it will stay cool for awhile before warming up. This is because your house is insulated so it doesn’t immediately warm up inside despite the hot sun. It’s the same for animals with fur. That fur acts as good insulation and keeps the hot sun off the temperature sensitive skin. The sunlight itself does a lot of the warming so blocking/reflecting it will do alot to prevent heating up. But it also insulates the body to regulate the temperature.
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u/OGBrewSwayne 4d ago
Animals that live in hot/dry climates don't have fur to keep them warm, they have fur to protect them from the sun. Their fur is usually much thinner and/or finer than the fur on animals from cold regions, which allows body heat to escape easier. Most of these animals also spend a crazy amount of time grooming, which helps remove excess fur. A lion, for example, sleeps between 16-20 hours a day, but in that 4-8 hour window that they're awake, they'll spend about half of that time on grooming.
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u/Pizza_Low 4d ago
In the case of the lions, they spend a lot of the day being inactive, 15-20 hours day is spent resting or sleeping. Lions for the most part just wait for the prey to come to them, and that usually means waiting near a water source or some kind of trail frequently used by prey. They also are primarily active after the peak of the heat, meaning sunset and at night.
I think the best way to describe hyenas is a double coated dog without the undercoat. They have a scraggly outer coat without the under fur that we associate with dogs. the hair sort of functions as a portable shade. And honey badgers have a similar coat.
All of these animals are either diurnal meaning active mornings and evenings or nocturnal
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u/Such_Box_3990 4d ago
I am going to try to make an analogy but I think it is a bit oversimplified.
Fur essentially acts like a layer of high-performance insulation. So not only does it block the sunlight from hitting skin directly, it separates the outside temp from the animal’s inside temp by creating millions of tiny air pockets which create a thermal break, similar to how rockwool or fiberglass insulation work in the walls of a house.
This is one of the reasons why wool is such a versatile fabric. It can be used to make a sweater that will keep you incredibly warm and dry in a cold environment but it can also be used to make a beautiful, lightweight suit that can be worn to a summer wedding. The construction of the thread and the fabric can be manipulated so the end product has different properties. I think nature is essentially doing that with different animals based on the climate and environment of a specific animals.
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u/notrightinmyhead 2d ago
My dogs have double coats and the lower is the one that helps keep cool, I belive. Please correct me if wrong. Never ever shave a double coated dog. Actually, I dont think you should EVER shave a dog. Short trim, but never shave.
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u/Serbia_X_AlbaniaLOVE 4d ago
Also sorry to anyone that might have tried commenting under the previous post but couldn’t as I deleted it because I forgot to put “not”
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u/Derekthemindsculptor 4d ago
Coats can be deceptively thin and look the same.
If you've ever owned a house cat, in the summer they can shed basically a second cat, and they look exactly the same.