We run the world, and are at an all-time population surge, but what is it that makes humans truly unique? Sure, we have critical thought, art, and altruism, but there are a number of other behaviors and traits that set us apart, and make us incredibly complex creatures. For hundreds of years, experts have been working to better understand our biology, psychology, and behavior. It’s a daunting task, however, and although we have come a long way in our journey to understand ourselves as a species, there is a great deal that remains a mystery.
These unexplained phenomena can be intriguing to examine. We do so many things in our daily lives without thinking about them, we may not even realize how noteworthy they are. Yet when we look closer, we learn that our bodies work in fascinating ways we do not yet completely understand, which we guess makes the mystery of the human experience another unique aspect of our existence.
That said, science has been able to uncover several distinctly human traits that are shared with no other species – though it hasn’t necessarily found out their causes: why is it, for example, that humans are the only animal that sheds tears when they are sad? Is there a reason why there are more serial killers born in the month of November than any other month? When it comes to such questions, science is still at a loss for words, but that doesn’t mean it isn’t fascinating to learn about the singular and downright bizarre things that make us, well, human. Read on to discover weird and thought-provoking facts about what sets us apart a human beings.
Nobody knows why we kiss
In television, movies, and popular music, kissing appears to be a universal way to show affection. However, a 2015 study found that fewer than half of 168 global cultures surveyed engage in the “lip-to-lip contact” that we call kissing – so maybe Drew Barrymore’s character in Never Been Kissed is not as unique as she thought she was. Some cultures express affection through different types of face-to-face touching instead of kissing. A number of experts believe that kissing can protect humans against certain viruses, but others claim that people do it simply because it feels good.
Humans are the only mammal that likes spicy food
Eating a hot pepper is painful, there’s no doubt about that. Yet unlike other mammals, many humans enjoy this self-induced pain. It’s not uncommon for people to pour on the hot sauce at mealtimes, raising the spice-level of their food to just below unbearable. Some, in fact, are so extreme that they choose to sample sauces so hot, you have to sign a waiver to taste them. This unique taste preference cannot yet be explained by scientists. Some experts claim that people like chilis because of their health benefits, which may include lowering blood pressure, while others argue these perks aren’t substantial enough. Perhaps people simply enjoy a little pain, introducing a bit of thrill during their meals.
Many musicians are also good at math
A notable number of famous musicians were also expert mathematicians, and vice versa. Albert Einstein was a renowned violin player in addition to a mathematical genius. He reportedly played classical music to help himself solve problems. Why are math and music so intertwined? There are a number of proposed explanations to this correlation but nobody knows the answer. It could be genetic, because music and math activate related sections of the brain, or because music theory is based around mathematical formulas. So do you want to be better at math? Perhaps think about taking up the piano!
Tall people are at a higher risk of cancer
Being tall is often seen as a desirable trait. Tall people proudly list their height on dating websites, models are frequently taller than average, and tall people have a built-in benefit when playing a number of sports. However, according to World Cancer Research Fund International, tall people also have an increased risk of six types of cancer. For every added 5cm in height, the risk of being diagnosed with certain cancers increases. Although this sounds like bad news, it’s not the full story. Tall people may also have a lower risk of other diseases such as diabetes, strokes, and heart attacks.
November is the birth month of more serial killers than any other month
Does your birth month affect your future? Those who believe in astrology say yes. But nobody has an explanation for the fact that more serial killers were born in the month of November than any other month. 17 known serial killers were reportedly born in November, including Ted Bundy (seen here) and Charles Manson. That’s way more than the average of nine born in other months. A 2005 study also found that those born in November tend to grow up to be more pessimistic in general. But don’t worry – just because you were born in November doesn’t mean you will become a serial killer!
More people have heart attacks on Mondays than any other day of the week
Mondays get a bad rep. People tend to dread the first day of the work week, but Mondays may be even worse than we thought. A 2017 study conducted in Sweden found that most heart attacks occur on Mondays. The study went on to show that the risk of having a heart attack is 11% higher on Mondays than on any other weekday. Young people have an even higher risk: their risk of heart attack is 20% higher on Mondays than the rest of the week.
There is no known scientific explanation for why people blush
Blushing is the human body’s way to make sure everyone knows when you are embarrassed. But only humans display this facial flush. Blushing occurs due to the release of adrenaline in a situation that makes people nervous or uncomfortable. This speeds up the heart rate and dilates blood vessels, causing the veins in the human face to react. Then, the dreaded pink flush appears on your cheeks. This display of embarrassment has no known evolutionary or scientific explanation.
Humans only need one of their lungs to survive
Humans are born with a number of paired organs including kidneys and lungs. However, they can survive with only one. Many people live a normal life with only one kidney following an accident or illness. It is also possible to donate a kidney to someone in need. Perhaps more surprisingly, people can also survive with one lung; it expands to fill the space in the chest left empty when the other lung is removed. Scientists do not agree on the reason why people are born this way, but it is a lifesaver for many who have suffered from injury or illness.
Scientists do not know why people yawn
Yawning is contagious. You see someone across the room open their mouth wide and breathe in deeply and you can’t help but do the same. But why do we do it? Yawning is an involuntary reflex that often occurs before or after sleep, or when a person is bored or lacking stimulation. A number of theories have been proposed to explain why we yawn including to convey boredom, to cool the brain, or to pump more oxygen into the blood. However, there is no accepted explanation for the common phenomenon.
Men with a relatively long ring finger scored higher on their math SAT
Men with longer ring fingers relative to their index fingers had higher math scores on the SAT, according to a 2007 study from the University of Bath. Finger ratios did not predict math scores for women, however. Instead, they were correlated with higher SAT verbal scores. The reason for this connection is still a mystery. Experts predict that hormone levels that affect the growth of fingers in the womb may also play a role in brain development, but the way that this hormone affects finger growth is not clear.
Balding or gray-haired men are more likely to have heart disease
Young men who lose their hair or go gray prematurely have a higher risk of heart disease, according to a number of studies conducted around the world. A research project in India showed a greater percentage of men with heart disease have gray hair or are balding compared with healthy men. In addition, a study of 37,000 people in Japan showed that balding men are 32% more likely to have heart disease. The reason for the correlation is not known.
35% of entrepreneurs are dyslexic
Dyslexia is a learning challenge that makes it difficult to read and write. It affects around 10% of Americans. Despite struggles in the classroom early on, a large number of dyslexics go on to have successful entrepreneurial careers. A 2007 study of entrepreneurs in the United States revealed that 35% of them identified as dyslexic. The researchers hypothesized that dyslexics develop a number of other skills to compensate for their difficulties with language. These may lead them to become creative problem solvers, skilled in oral communication, and good delegators.
People with more moles age more slowly
Having a larger number of skin moles is correlated with slower aging, according to a 2007 study. Moles are often connected with having younger skin as well as better bone density. However, moles are also linked to a higher risk of skin cancer. These skin markings often appear in childhood and go away as a person ages. The reason for the correlation is unknown, but experts say it is most likely related to differences in the DNA strands that carry the person’s genetic code.
Men attracted to other men are more likely to have a counterclockwise hair swirl
Your hair can say a lot about you. Aside from chosen hairstyle, color, and cut, the direction of a man’s hair swirl may also be correlated with his romantic orientation. There is a higher percentage of counterclockwise hair swirls in men primarily attracted to other men, than found on average in both men and women in general. According to a 2004 study, 29.8% of these men have a counterclockwise hair swirl, compared with only 8.4% in men and women at large. All in all, it’s a hair-raising phenomenon.
Humans are the only animal that shed emotional tears
Why do we shed tears when we are sad? Scientists do not agree why humans cry the way we do. In fact, humans are the only animals who shed tears because of our emotions. Other animals only tear up to get rid of irritants in their eyes. Experts think that humans may cry to display their distress to others or to draw the attention of a caretaker. Not all humans cry the same amount, however. Studies show that women cry more frequently than men, and women from richer countries cry more frequently than women from poor countries.
A human tongue has a unique print, just like fingers
The human tongue is incredibly important for daily life – it helps you eat, speak, and swallow. But it also has a unique print just like your fingers! Although scientists don’t know why tongues developed this way, researchers have begun to explore the potential of using unique tongue prints to identify people. Chinese researchers are even working on a 3D tongue image database. So if you want to protect your identity, don’t stick out your tongue!
The liver is the only organ that can completely regenerate
The ability to regenerate body parts is something out of superhero comics that has long fascinated humans. Amazingly, the human liver can regenerate itself! As little as 25% of the liver is required to regenerate, returning to full size. The liver is the only human organ that can do this. It is crucial to the health of our bodies because the liver is exposed to a number of chemicals, causing cell damage. In order to prevent serious liver damage, the organ rebuilds itself when harmed.
There is no known explanation for déjà vu
You know the feeling: you’re walking through a place you’ve never been, or coming across a situation you’ve never had, yet you’re sure it has happened before – much like Guy Pearce in Memento (shown here), as he repeatedly tries to piece together the fragments of his life. Déjà vu is just such a feeling of familiarity, which many people sense when they feel they are in a situation they have experienced in the past. Scientists have yet to come up with an accepted explanation for this eerie, almost supernatural experience.
Human heartbeats can change depending on what music you listen to
Do you ever feel like your heart is beating with the music? It may be more than just a feeling! A 2009 Italian study showed that human cardiovascular and respiratory systems change to mirror the tempo of music. The reaction occurs in musicians and non-musicians alike. It has long been accepted that music has an affect on human emotions, but it could have the ability to regulate body systems as well. This shows that we are only beginning to understand the power of music on our bodies.
Fingernails grow faster than toenails
Have you ever felt like you need to cut your fingernails much more frequently than your toenails? It’s true: fingernails grow two to three times faster than toenails. So go ahead and get that pedicure – it will most likely last longer than your manicure. Fingernails grow about 3.5-4mm per month and toenails only grow between 1.7-1.8mm per month. However, nobody knows the reason for this significant difference. The rate of growth of both fingernails and toenails is affected by age, gender, diet, health, and a number of other factors.