The question why our earliest ancestors lost their hair when fur would
have been beneficial to them – for keeping warm on cold nights, for
example – was pondered by Charles Darwin, the
famous evolutionist: “No one supposes that the nakedness of the
skin is any direct advantage to man.” He concluded that the
reason hominins lost their hair was sexual selection. In other
words, we prefer our partners to have little hair. But what caused our
ancestors to start losing their hair before this preference set in?
When she is chewing the grass,still listening the sound around the
land.Suddenly,she is turning ears and stop chewing.And then she raise up
her head for few second.The antelope try her best to escape.Because she
realizes the cheetah behind the bush.Also the cheetah cannot let the
prey run away.He is follwowing the antelope.He is stretching his
forearms and showing up his sharp claws to hunt the prey.The antelope
has turned her dirction so that the cheetah fails first attack.The
cheetah cannot give up the hunting,same like the antelope never give up
to escaping.But the antelope is too tired to run.The next second she
becomes the cheetah’s dinner.
In fact, persistence hunting remained in use until 2014, such as with
the San people of the Kalahari Desert.
In Africa grassland,it’s the hottest summer in this year.The ground is
almost burned by the heat.Now survives and waits for the rainfall is the
biggest chanllege for these animals.These are group of antelopes is
migrating to somewhere there are more food and water.The long distance
of migration make them tried and now they need for a rest and eats some
Not only the herbivores needs to struggle with the horrible
tempreature,but the carnivores cannot without meat to survive.A hungry
cheetah is staring at his delicious dinner.He is the fastest animal on
land.In few seconds,he can run as fast as a car going on the highway.But
only he has one chance to catch one of them.If he lost,he will die.So he
is hiding in the bush and finding the best of opportunity to take
action.It seems the God want to help the poor cheetah.An antelope is
leaving her group to finding more grasses.She don’t notice the eyes
behind the bush.
Humans are the sweatiest primates on Earth. They have up to 5 million
sweat glands,which produce about 12 litres of sweat per day. It’s
this propensity to sweat that accounts for our hairlessness and has
allowed us to thrive. It might help to remember this next time you’re
surrounded by sweaty hairless torsos in the gym!
Compared to other large mammals on Earth, we humans have relatively
little hair. This obvious fact is not so strange until we look at our
closest living relatives in the animal kingdom – chimpanzees and other
great apes. Why, might we ask, have we evolved to be almost hairless
when all other primates are still covered in fur? In
fact, bizarre as it may seem, our lack of hair has been the key to
our evolutionary success as a species.
Here’s where our special adaptations come in. The tendons and muscles in
our legs are very springy. They act like a pogo stick, converting
kinetic energy from the aerial phase into elastic potential energy,
which we can use later.
The most likely hypothesis to explain the loss of hair is that it
became necessary when early hominids 皇家88平台，moved to a more
open savannah habitat around 2 to 3 million years ago, when they
started to hunt big game.Hunting in open savannah meant being exposed to
the strong heat of the sun for several hours in the day and being in
danger of overheating. Being covered in hair prevented our ancestors
from losing heat fast enough. So, as Peter Wheeler, of Liverpool John
Moores University in the UK, explained, losing hair allowed them to
develop the ability to sweat and therefore to cool down. Early humans
could, as a consequence, be out at midday hunting and foraging. “It
would be [an] enormous advantage to be able to spend the entire midday
foraging,finding mates or fighting enemies”, Tamás Dávid-Barrett of
Oxford University says. “Sweating allows that, and for sweat to be
efficient you need to be mostly hairless”. The meat from hunting animals
gave early humans the energy to fuel their growing brain.