You have a blind spot in each of your eyes.
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That’s because humans have an inside-out retina. This means that nerve fibers are in front of the retina, blocking light. But in octopuses and squids, nerve fibers are located behind the retina, so they don’t have a blind spot.
You can check out your blind spot by looking at this GIF. Close your right eye and stare at the cross with your left eye. You’ll notice the red dot disappear then reappear in your peripheral vision. This is your blind spot.
Your wisdom teeth causes a whole bunch of problems.
Wisdom teeth are seriously a bitch. That’s because your tiny jaw is already too overcrowded.
Scientists say wisdom teeth were useful when we had bigger jaws and a tougher diet that wore down our teeth. But now the molars just cause pain and infection.
If you have balls, they hang outside your body where — let’s face it — they’re pretty vulnerable.
Comedy Central / Via giphy.com
Some scientists say that sperm production is best at temperatures a few degrees cooler than your body temperature, which is why your balls just dangle there all out in the open.
But this makes them so incredibly vulnerable and defenseless. Anybody who’s been kicked in the balls knows this danger all too well. Surely it would make more sense for your testicles to be safely shielded inside your body, like in elephants. But that would just be weird when you think about it.
Wiggling your ears is completely useless.
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Some people can wiggle their ears, but there’s absolutely no need to be able to do this. Unless you’re a cute little cat. Cats can hear birds or predators better when they move their ears. Scientists say our ability to do this might be a leftover trait from one of our shared ancestors
Nowadays, ear wiggling is “a dubious talent that has no apparent function aside from entertaining young children,” wrote biologist Lewis Held in his book Quirks of Human Anatomy (Cambridge University Press, 2009).
Now let’s talk about the biggest mystery of all time — male nipples.
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According to Lewis Held, male nipples are completely useless. Scientists theorize that male nipples may have been a leftover trait from the womb (everyone starts out essentially female as a fetus, and then later male sex organs develop). But nobody is really sure.
You had gill-like structures in the womb.
Marshall University / Via musom.marshall.edu
These are called branchial arches and they are a leftover traits from our fish ancestors, wrote Held.
These embryo “gills” eventually help form your face, neck, mouth and other structures, but Held said that those things could develop without the gills.
You can choke really easily because there’s only a little flap of tissue covering your windpipe when you eat.
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Whenever you swallow food, a flap of tissue called the epiglottis covers your windpipe (trachea) so that food goes down your foodpipe (esophagus) to get to your stomach. Choking happens when the epiglottis messes up and food gets in your windpipe, wrote Held.
But human babies and other mammals have an epiglottis that is all the way up in the back of their mouths. Their larynx (voice box) is also all the way up, allowing them to breathe and eat at the same time (which we can’t do). But this also means that they don’t have the vocal ability to speak.
Speaking of choking, you can’t really go that long without oxygen.
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But other animals can survive long periods without oxygen. Sea turtles can hold their breath for three hours, wrote Held. Humans can barely hold their breath for four minutes without serious brain damage. Other animals breathe less oxygen when they hibernate. And there’s even bacteria that can grow without oxygen all together.
Held believes that we never really adapted to survive with little oxygen, because there was no evolutionary need. It was rare for primates to die from drowning, for example.
You can’t naturally synthesize vitamin C.
Paramount Pictures / Via giphy.com
Many vertebrae species can produce vitamin C in their bodies, but humans can’t which means we have to consume it in our diets (think orange juice). Interestingly, we have the gene to synthesize vitamin C, but it was silenced due to a mutation that occurred in our early history.
If you don’t eat enough vitamin C, then you’ll end up with scurvy.
Your pelvis really gets in the way of giving birth.
Nucleus Medical Media / Via youtube.com
Humans have a really small pelvic opening. And babies have really big heads. See a problem here? It’s a tight fit for the baby to enter the birth canal. According to Held, birth would be safer and less painful if the baby exited somewhere near your navel (like in a cesarian section). Imagine a baby coming out of your belly button. That would truly be a miracle of birth.
Interestingly, spotted hyenas have it worse. Pups exit out of their mother’s extremely narrow clitoris. OUCH.
If you were born male, your prostate might cause some issues when you’re older.
National Cancer Institute / Via commons.wikimedia.org
And this is because your urethra (that tube that urine flows through when it exits your penis) passes through your prostate, instead of going around it (which would be the more logical set up). Sometime around middle age, men’s prostates start to enlarge. Your prostate can get so large, in fact, that it strangles your urethra, which can make it hard to pee.
There are way too many bones in your feet.
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There are around 26 bones in each of your feet (around one-fourth of the bones in your entire body are located in your feet). And this causes a whole bunch of problems like broken ankles and sprains. You can thank our ape-like ancestors for all those bones — They needed it when they grabbed onto tree branches with their feet. But this design is not really useful when you’re walking upright.
Your anus and genitals are too close together.
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This means it’s easy for bacteria from your anus to travel to your vagina or penis, causing uncomfortable UTIs. This is a bigger problem if you’re a woman, since the distance from your anus to your urethra (the tube you piss out of) is shorter than in men. But men can still get UTIs regardless.
Finally, this is probably our greatest flaw:
Disney / Via giphy.com
It’s always good to end on a positive note. Isn’t it?
