Humans are unusual animals by any stretch of the
imagination. Our special abilities, from big brains to opposable thumbs, have
allowed us change our world dramatically and even leave the planet. There are
also odd things about us that are, well, just special in relation to the rest
of the animal kingdom. So what exactly makes us so special? Some things we take
completely for granted might surprise you.
1. Speech
The larynx, or voice
box, sits lower in the throat in humans than in chimps, one of several features
that enable human speech. Human ancestors evolved a descended larynx roughly
350,000 years ago. We also possess a descended hyoid bone — this horseshoe-shaped
bone below the tongue, unique in that it is not attached to any other bones in
the body, allows us to articulate words when speaking.
2 Upright Posture
Humans
are unique among the primates in how walking fully upright is our chief mode of
locomotion. This frees our hands up for using tools. Unfortunately, the changes
made in our pelvis for moving on two legs, in combination with babies with
large brains, makes human childbirth unusually dangerous compared with the rest
of the animal kingdom. A century ago, childbirth was a leading cause of death
for women. The lumbar curve in the lower back, which helps us maintain our
balance as we stand and walk, also leaves us vulnerable to lower back pain and
strain.
3.
Nakedness
We
look naked compared to our hairier ape cousins. Surprisingly, however, a square
inch of human skin on average possesses as much hair-producing follicles as
other primates, or more — humans often just have thinner, shorter, lighter
hairs. Fun fact about hair: Even though we don't seem to have much, it
apparently helps us detect parasites, according to one study.
4.
Clothing
Humans
may be called "naked apes," but most of us wear clothing, a fact that
makes us unique in the animal kingdom, save for the clothing we make for other
animals. The development of clothing has even influenced the evolution of other
species — the body louse, unlike all other kinds, clings to clothing, not hair.
5.
Extraordinary Brains
Without
a doubt, the human trait that sets us apart the most from the animal kingdom is
our extraordinary brain. Humans don't have the largest brains in the world —
those belong to sperm whales. We don't even have the largest brains relative to
body size — many birds have brains that make up more than 8 percent of their
body weight, compared to only 2.5 percent for humans. Yet the human brain,
weighing only about 3 pounds when fully grown, give us the ability to reason
and think on our feet beyond the capabilities of the rest of the animal
kingdom, and provided the works of Mozart, Einstein and many other geniuses.
6.
Hands
Contrary
to popular misconceptions, humans are not the only animals to possess opposable
thumbs — most primates do. (Unlike the rest of the great apes, we don't have
opposable big toes on our feet.) What makes humans unique is how we can bring
our thumbs all the way across the hand to our ring and little fingers. We can
also flex the ring and little fingers toward the base of our thumb. This gives
humans a powerful grip and exceptional dexterity to hold and manipulate tools
with.
7.
Fire
The
human ability to control fire would have brought a semblance of day to night,
helping our ancestors to see in an otherwise dark world and keep nocturnal
predators at bay. The warmth of the flames also helped people stay warm in cold
weather, enabling us to live in cooler areas. And of course it gave us cooking,
which some researchers suggest influenced human evolution — cooked foods are
easier to chew and digest, perhaps contributing to human reductions in tooth
and gut size.
8.
Blushing
Humans
are the only species known to blush, a behavior Darwin called "the most
peculiar and the most human of all expressions." It remains uncertain why
people blush, involuntarily revealing our innermost emotions. The most common
idea is that blushing helps keep people honest, benefiting the group as a
whole.
9.
Long Childhoods
Humans
must remain in the care of their parents for much longer than other living
primates. The question then becomes why, when it might make more evolutionary
sense to grow as fast as possible to have more offspring. The explanation may
be our large brains, which presumably require a long time to grow and learn.
10.
Life after Children
Most
animals reproduce until they die, but in humans, females can survive long after
ceasing reproduction. This might be due to the social bonds seen in humans — in
extended families, grandparents can help ensure the success of their families
long after they themselves can have children.
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