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Vestigial -

Any part in the human body that doesn’t serve a valid function is known as a “vestigial organ.” Although they were once essential, these body parts have lost their original function.

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Auricular muscles -

While most mammals have the ability to control their ears and point them in whatever direction they wish, humans have largely lost this ability over the millennia. But that doesn’t mean the muscles (known as auricular muscles) have disappeared.

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Auricular muscles -

Some people are able to wiggle their ears using their auricular muscles, but this is incredibly rare and also rather insignificant.

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Darwin's tubercle -

Most people are born with a bump on the rim of their outer ear. This bump is thought to be a remnant of a joint that once allowed humans to fold their ears over the ear canals. In more modern times, this is considered a malformation.

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Gallbladder -

Although the gallbladder is responsible for pumping bile (a fluid produced by the liver to break down fatty foods) into the small intestine, this was only really worthwhile for our hunter-gatherer ancestors. After all, they would feast heavily on fat and protein in order to retain energy during periods of famine.

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Gallbladder -

Modern humans don’t need the gallbladder as much. In fact, when issues with the organ arise, it can be removed entirely, and the body compensates by distributing bile through other means.

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Plica semilunaris -

On the inside corner of every person’s eye is a fold of tissue known as the plica semilunaris. Birds, reptiles, and some mammals use that fold as a membrane to keep their eyes moist, but humans have lost the ability to control this. In fact, this membrane is incredibly rare among primates.

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Plica semilunaris -

The plica semilunaris is largely useless, and many medical patients have been known to remove it in order to narrow or block their tear ducts.

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Flat feet -

The human foot has adapted to run fast and far using a double arch system. The first arch goes from the front to the back (known as a longitudinal arch), while the second goes from side to side to reduce the use of muscles. Other primates, such as chimps or gorillas, do not have these arches.

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Flat feet -

Other primates have flatter feet than humans, and some people have been born with genetically flat feet (scientifically called pes planus). Anyone born like this uses far more muscles to run, although humans have largely evolved beyond this.

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Male nipples -

When fetuses develop in the womb, all of them start out the same way (regardless of sex). For males, testosterone eventually kicks in and gives them male organs, but their nipples form way before the hormones actually arrive.

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Male nipples -

Biologically, nipples are designed for new mothers to give milk to their children, but males cannot lactate under any natural circumstances.

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Body hair - The primary function of hair is for the regulation of body temperature. Primates in the wild have hair all over their bodies because they need protection from the elements, but humans only have hair in select spots.

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Body hair -

Humans evolved the ability to regulate body temperature through sweating, since our sweat glands are bigger than those of our primate cousins.

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Arrector pili muscles -

Arrector pili muscles are responsible for giving humans the effect of goosebumps on their skin. When the muscles are stimulated, they contract and pull the hair, causing them to stand upright. But these muscles only had significant relevance when our primate ancestors were covered in hair.

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Arrector pili muscles -

Much like cats and dogs that raise their hackles when threatened, the arrector pili muscles in our ancestors were designed to make us look bigger and more imposing to enemies. Naturally, we evolved beyond the need for them, even though they’re still there.

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Vomeronasal organ -

Many animals (including reptiles, amphibians, and mammals) have a structure in their noses known as the vomeronasal organ, which helps to detect pheromones. Interestingly, most humans don’t have this, although some are still born with it.

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Vomeronasal organ -

Medical evidence has shown that people who have this organ (which is located at the roof of the nasal cavity) do not have the pheromone-detecting capabilities that other animals have, which means that the organ is practically useless.

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Appendix -

Perhaps the most famous of all the body parts on this list, the appendix has remained an enigma for much of scientific history. Not only is it a dangerous organ that sometimes needs to be removed, but some people are born entirely without it.

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Appendix -

Naturalist and geologist Charles Darwin was the first to propose that the appendix may have once aided our herbivorous ancestors in digesting hearty plants. Other scientists believe that the appendix is a reservoir for helpful gut bacteria. The truth remains to be seen.

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Fifth toe -

The pinkie toe was once used by our wild ancestors for gripping onto branches and climbing through trees, and this can still be seen in our primate cousins. But today our bodies don’t need this, and we have largely evolved to find other ways to maneuver.

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Fifth toe -

Contrary to what many people might think, the pinkie toe is also unnecessary for balance. Indeed, it’s actually our metatarsal bones in the middle of our feet that are crucial for allowing us to run, walk, and balance.

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Wisdom teeth -

The wisdom teeth located at the back of a person’s jaw would have once helped our ancestors chew through tough food, but now they’re practically pointless. Indeed, wisdom teeth oftentimes don’t even fit, and they need to be removed.

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Wisdom teeth -

Interestingly, teeth never change size, which means that every person is born with them lodged inside their gums, just waiting to emerge. But not all people have wisdom teeth, and experts say that approximately a third of all humans are born without them.

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Palmaris longus -

Many of the muscles in the human body are remnants of our ancestors who once climbed through trees. One of these is the palmaris longus, a muscle that stretches from the wrist to the elbow.

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Palmaris longus -

As many as 10% of people are born without a palmaris longus. As humans began walking on two feet about 3.2 million years ago, the need to hang and swing from trees became obsolete.

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Plantaris muscle -

Similar to the palmaris longus, every person has a muscle in their leg that has also become largely vestigial, known as the plantaris muscle. At this point, it is nothing more than a useless tendon, stretching from the knee area down to the heel.

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Coccyx -

The tailbone (also known as the coccyx) is another useless body part that is a remnant of our primate ancestors. Our ancestors once used tails to swing through trees, but they evolved to walk on four legs and then two legs, and so the need for a tail became pointless.

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Pyramidalis muscle -

The pyramidalis muscle is shaped like a triangle in the lower abdomen, and it is possibly one of the strangest body parts on this list. Experts are uncertain what function the muscle serves, but they believe it may have helped our ancestors move around before they started walking on two legs.

Sources: (Wired) (Live Science) (Business Insider) (University Health News) (Las Vegas Sun)

See also: Animals that can regrow body parts

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