A straightforward answer to your concern is that allmammals have hair. It is one of the criteria thatscientists use to divide mammals (to separatethem from other vertebrate pets such together birdsand reptiles). This way that also whales,elephants and dolphins have body hair!Whymammals emerged hair in the very first place we canonly assumption: v at, due to the fact that no one to know for sure whyevolution go one method or the other. Yet a goodguess would certainly be the we developed hair (or fur) toconserve human body heat. Mammals space warm-blooded,which way that we require a high inner bodytemperature come survive. Very few animals otherthan mammals room warm-blooded. (For example, theinternal temperature of many fish and reptiles isdictated by the temperature of your environment.In Antarctic fish, body temperatures deserve to be closeto freezing! To find out why the organization in thesefish don"t freeze, check out this web page:http://www.tc.cornell.edu/Edu/SPUR/SPUR94/Reports/SPUR_Adam_Report.html.)One benefit to being warm-blooded is that warmermuscles can contract faster, so animals with highbody temperatures deserve to fly or operation on short notice,even as soon as it"s cold outside. (Insects can"t dothis!)A great of hair or fur also as thinas the hair on our arms can trap air and also create aninsulating layer in between our skin and the coldertemperatures outside. The thicker the fur and theoilier that is the much better the insulation. Obviously,the fur on a seal is walking to be a much betterinsulator 보다 the hair on our arms, yet even alittle little of hair helps. Birds, although notmammals, perform this insulation trick also: lock havea layer of really fine feathers right beside theirskin (called down) i beg your pardon traps air and keeps themwarm. Humans loose most the our warmth from ourheads, so it renders sense that we have a lot ofvery special hair on our heads. Ours legs and armshave too many of an effective muscles and are easilychilled, therefore it makes sense that they have morehair too. Our eyelashes protect our eye from dustand other little particles. Our eyebrows might helpto cushion the large bones above our eye sockets,which stick out to safeguard our eyes and foreheads.Other facial hair is an ext complicated, and iscontrolled by hormones (this is why men havebeards and also women carry out not, and why guys do notdevelop beards till they go through puberty).There has actually been a gradual trend in the direction of aloss of human body hair in human being evolution. MY theory ofwhy this is (unproven and untested!) is the it iseasier to boost body temperature when cold thanit is come decrease body temperature whenoverheated. Humans can shiver, burn stored fat, oruse shelter and also clothing to remain warm, but to cooldown we should sweat, and also this entails a lot ofwater loss. Excess hair would certainly make overheatingeven much more likely. Since humans can quickly diewhen too warm or too dehydrated, evolution may havesteered united state toward less body hair. However, thisdoesn"t define why mice the live in the desertstill have thick coats of fur.Answer 2:
Biologists look in ~ questions prefer this in twoways: What does it do for us now? and How walk weget it?All mammals (things that provide milkto your young) have hair.We"re mammals, therefore itmakes sense that we have hair. For many mammals,hair is essential as insulation, keeping body heatin once it"s cold and giving protection from hotsun. Human hair can be advantageous for maintaining thehot sun off our head and neck, but it doesn"t domuch to save us warm.Another questionmight it is in "why do we have so tiny hair?" Thereare few bald mammals. Some marine mammals likewhales and dolphins have no hair when they"re born(though they have actually hair together fetuses). Hair createsdrag in water (human swimmers often shave theirbodies). Another bald mammal is the nude molerat, which resides in the hot sand of the SouthAfrican Deserts. Some civilization say they"re theugliest mammal in the world. You be thejudge:http://web3.si.edu/organiza/museums/zoo/zooview/exhibits/nmrats/nmrhome.htmBiologistsmight imply that we have actually so small hair becausewe progressed in a warm climate where some protectionfrom the sun was good, but an ext hair made us toohot. As soon as we relocated to cooler climates, clothes,fire, and also shelter aided us survive.Thesecond component of your question is why we have actually itwhere we have it. All of our bodies other than forour palms and also the soles of our feet have actually somehair, it"s simply short and fine. In truth chimpshave around as numerous hair follicles as we do, it"sjust the each hair is longer. In ~ puberty, bothmales and females get hair in their armpits andpubic area because of hormonal signals. Some peoplesuggest the this actually helps to host in odorsthat signal that a person has reached sexualmaturity. What do you think?Males getfacial hair. This may be a signal the he hasreached, or is reaching, physical maturity.
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Othermale pets have signals favor this too, forexample the lion"s mane. Why would certainly this it is in animportant signal?Thanks for asking.