Do animals and human shade the same tear?

Nirvik, a 10-year-old boy, was sobbing hard while her mom forced he to bathe. His eyes clearly reflected the disappointment as his mother poured water down his spine. Cold water shivers his body to the core, and he seemed even displeased. His howling was clearly irritating the whole village.

Indeed, I also have vivid weeping memories – special ones while watching a couple of movies. We had a family break down while watching “Sukha-Dukha”, a Nepali drama and also an English flick called “It’s a wonderful Life”. I couldn’t help but cry my eyes out during the watch.

And talking about crying, well, don’t you wonder about tear sometimes? And more importantly, why does your vision need to be blurred for the sake of your emotion anyway? Even if we try to personalize our cryings, tear, as it turns out, is not really something humane. Animal cry out of pain, suffering, and reflex actions, but we shed tears for one additional purpose: Out of FEELINGS. So the basic reasons for which we tend to weep seem to vary.

And there are numerous tear origin theories. I jumbled through various literature, and found that some ancient western folks believed that tears were product of heart. As the fundamental material making the heart weakens, tears are shed. ‘Crying essential weakens our core heart’, they believed.

Another western theory modified this prevailing concept a bit. Powerful emotions like ‘Love’ heats up the heart. So, the heart gets vaporized and its material fly up. They are cooled and condensed as they reach to the head. And just like the cloud that condensed and runs down the sky while raining, the vaporized heart material – so-called tears – fall down in the form of tears through the small pores near the eye socket. Just wonder the level of imagination, people used to have back then.

Let's jump from people to scientists. Some scientists used to imagine from even stranger angle. William Frey, believed that tears actually removed toxic substance from the blood. He might have connected the tear evolution with that of sweat. Social scientists had their own theory. They believed that crying was actually different in human (from the rest of the animals) for a social purpose. ‘As a hunter, gatherer and as an individual of a specific tribe, the tears signaled your parties that you needed help. This in turn, enhanced the bonding behavior essential in humans.’

This weird fluid, seated up in the head, flows whether we are too upset or too jubilant. Not only for pain but also for pleasure. In a way emotion gets involved. So, all in all, emotional tears and non-emotional tears, are they any different? It turns out they actually are. Though it's pretty insignificant but evolution goes micro level. Amount of a protein involved in crying out of Emotion is relatively higher than if you cry while chopping off Onions. These proteins supposedly stick more in your skin (maybe an evolutionary reason) making it visible across your mates/parties/tribes.

Emotion is an integral part of human biology. And it's not definitely innate to humans only. But the way it has evolved with our evolution has a distinguishing role. So its humane relation is quite interesting. This salty fluid, what good do they do for us?

It actually has three different origins in our eyes, as Hank Green explains in this brief video. First the basal tears, I would like to call it, the Keeper. It keeps the eye moist all the time, helping in eye movement, adjusting as per the need and lubricating for the easy movement.

Second one is a reflexive tear. When any dirt or chilies or the onion gases get into your eye, out of nowhere tears comes up - helping you get rid of all that.

And finally the emotional one. Even your memories, experience, and feelings can turn it on. It has the origin in your brain. That’s why the chemical composition of emotional tear is different: with more of Prolactin protein.

But it turns out that a few of our prevailing beliefs about unique human tears might have been debunked as a result of a recent study.

Arrianne P. Oria and his team from Brazil carried out a comparative study among many animals and found that essential fluid composition of tears - like some minerals, ions, and solutions – remain essentially the same across different class of animals like birds, reptiles and men. Oria included the tear samples of healthy captive animals collected for conservation effort. The animal included hawks, owls, parrots, tortoise, sea turtles and 10 volunteers representing human. The amount of ions (i.e. sodium, chloride), protein and urea were found to be similar in all collected samples. That’s strange. And the study has implication figuring out the evolutionary history of eyes across different animal categories. 

Elephant shading tear

May we need in-depth analysis of tear origin in animals as well. Shading tears out of emotional response in animals have always been questioned, and we need dedicative research in that field as well. In the meantime, let's be grateful when we shade tears. When everything seems wrong and you cry, these salty fluids are the reminder that something is right. Imagine the pain of people who can't shade tears even while crying. Yeah, it's actually a syndrome - Sjogren's Syndrome Symptoms. Your body is still good, and thank god you are still shading tears.