Crying is a universal experience that all humans share, from the time that we’re babies to the age of adulthood, we all do it. But how much do people actually know about tears? Although crying is something we all share, not very many of us know much about these salty beads of liquid. This article will list nine different things you may or may not have known about tears.

There is More Than One Type of Tear

According to Lauren Bylsma, a Postdoctoral Scholar at the University of Pittsburgh, and her co-author Ad J.J.M. Vingerhoets of Tilburg University in the Netherlands, there are three different tears a human can produce. The first is basal tears, which are always present in our eyes, and are secreted for the purpose of lubricating, moisturizing, and protecting our eyes. The reflex tear is one that is produced for defending the eye against irritation from wind, smoke, and chemical irritants like Syn-propanethial-S-oxide, which is found in onions. There’s also some evidence to suggest that these tears are also chemically different. The third type of tear is the one we are most familiar with: emotional tears. One study from the 1980s stated that emotional tears may contain more protein than other tears, but the research isn’t conclusive.

The Composition of a Tear is Similar to Saliva

Saliva and tears are both made up out of proteins, salt, and hormones! In addition, they both come from the Exocrine glands, which are glands that produce substances to help your body. These substances include both tears and saliva, as they help keep a certain part of your body healthy. As saliva keeps your mouth dry, tears protect your eyes from irritants.

The Anatomical Reason Why Your Nose Runs After Crying

Bylsma stated that “the nose is running because the tears actually go in the nasal cavity…some of them end up in your nose, so your nose runs.” But for the headaches that appear after crying, Bylsma says that it might be related to the water loss we experience from tearing up, or because our muscles tighten up when we get upset.

Researchers Don’t Have a Solid Reason for Why we Cry

There are many theories circulating around about why we cry, but some scientists suggest that we evolved to cry as a distress signal. However, we cry without making any noise at all, not even a yelp! Bylsma explained that as humans develop over time, the things we’ve evolved to have can have multiple purposes. She said that “crying is a way to elicit support from others during times of distress.” Which explains why babies cry to get the attention of their parents, while adults might cry to elicit the sympathy of a friend or loved one. In an argument, crying is like a trigger to resolve an issue faster. After all, how could you get mad at somebody when they’re crying?

Women do cry more often than men, and the gender difference may be cultural

On estimate, women cry 5.3 times a month while men cry only 1.4 times a month. Furthermore, the average sob session for a woman is six minutes, versus the two to four minutes for a man. In one of her papers, Bylsma wrote, ”The amount of gender difference in crying also seems to vary with specific country characteristics. Surprisingly, in Western cultures with greater freedom and equal treatment for women, women cry more often than in more traditional cultures, whereas [the] differences between men in different cultures are less substantial…this insight strongly challenges the notion that crying is just an involuntary, reflex-like symptom, resulting from specific feelings.”

Crocodile Tears are Real

As written by one University of Florida researcher, Kent Vliet, in 2007, crocodiles do cry! But not because they’re sad. While studying several crocodiles, Vliet noted that five of them seemed to tear up while eating. In a statement, he said that it definitely wasn’t because they were grieving, because “when crocodiles take something in their mouth, they mean it.” The founder of Crocodilian.com, Adam Britton spoke to National Geographic and said, “Crocodiles appear to produce tears all the time. Their function is– like our own eyes– to lubricate the eye. This may be even more relevant for crocodiles because they have a third eyelid.”

Some people cry more than others, but why?

As reported by WebMD, people who have a trauma, those who are anxious, extroverted, or empathetic are more likely to cry. But it might just come down to individual personality differences. For instance, some people ignore or just aren’t as fazed at things that might cause the regular person to break out in tears.

There is “good” crying

In many of Bylsma’s papers, she describes the psychological relief through the open expression of emotions, also known as catharsis. Depending on the social situation, how good you feel after crying can differentiate. For example, if a person was crying in a comfortable situation, they would feel much better afterward. But if someone was trying to hold in tears in a place where they felt embarrassed and vulnerable, the effect would be just the opposite. There are also suggestions that emotional tears, which we know are different from basal and reflex tears, contain stress hormones that your body can release when you cry. Other scientists suggest that when you cry, your body releases endorphins that make you feel good. These are the same kind of endorphins released when you exercise or laugh.

Happy tears aren’t very different from sad ones

There’s not much of a difference between happy and sad crying since crying is just a period of intense emotional release. Bylsma explains one theory, where the body returns to a state of homeostasis after being overly aroused—whether negatively or positively. Right after that peak of arousal, crying can help the body return from that period to one of normal functioning.

Although these facts won’t change much about how you think about tears, it doesn’t hurt to know more about them. After all, learning new things is a way to learn more about yourself, and the world around you!