Why do humans cry?

Question

OK I'm not a moron, don't give me any "They cry because they're sad" answers! I'm interested in why the human being cries when it's sad/hurt because I'm sure no other animals do it. It just seems really strange when I think about it! Can anyone help?

Answer 1

Why is it that humans can be reduced to blubbering messes, while other members of the animal kingdom don’t seem to let out even a sniffle?

We have tear ducts to lubricate and protect our eyes from dust and other particles. The ducts are under the upper eyelids and produce a salty liquid—a tear-–-that gets spread throughout the eye after each blink. Animals too have the ability to produce tears, but not necessarily for the same reasons that we humans produce them.

Three types of tears are generated by the human eye. Basal tears protect the eye and keep it moist. Reflex tears flush out the eye when it becomes irritated. And emotional tears flow in response to sadness, distress, or physical pain.

Studies have shown that emotional tears contain more manganese, an element that affects temperament, and more prolactin, a hormone that regulates milk production. Sobbing out manganese and prolactin is thought to relieve tension by balancing the body’s stress levels and eliminating build ups of the chemicals, making the crier feel better.

But this minor physiological benefit aside, the most likely reason we produce emotional tears is because it’s a means of communication. Before babies can speak, they can cry. The only way for infants to express frustration, pain, fear, or need is to cry. Adults may use crying to bond with other humans. Expressing sadness can prompt comfort and support from peers. Different languages can provide barriers to spoken communication, but emotions are universal. There are also culturally acceptable reasons for crying that bring people together, such as at funerals or weddings.

Though there is a significant debate over whether animals have emotions and can express them, some animals do appear to cry for emotional reasons. Elephants seem to grieve when a family member dies and will guard the body and travel long distances to view it. Elephant experts at the London Zoo once told Charles Darwin that the animals do indeed mourn. Chimpanzees also appear to cry, but some scientists still insist that the tears released by these animals are strictly for cleaning the eye.

Whether or not animals shed tears for emotional reasons has yet to be scientifically proven. Humans, however, can and do dissolve into tears for any number of reasons. Cleansing the eye, relieving stress, conveying pain, communication, and societal assimilation can all lead to an empty tissue box. So weeping after that sappy movie might not mean that you are a total wuss after all. In fact, it may mean that you are behaving like a perfectly normal human being.

Besides protecting your eyes, the tear glands produce more fluid when your eyes are irritated. These extra tears are called reflex or irritant tears. And, when something makes you happy or sad, your tear glands will produce emotional tears. Used tears then drain down into two tiny openings on the brim of your upper and lower eyelids at the inner edge of your eyes, which lead to the nasolacrimal tear ducts next to the bridge of your nose. From there, they are channeled into your nasal cavity where they are swallowed or blown out with other nasal fluids. If there are too many tears, they will overflow your lower lid and run down your cheeks.

Answer 2

Moyah and Aaryan have some pretty decent answers, so I figure I'd just add a few things that they missed.

IN case you might not have noticed, the cornea of the eye is one of the few places where there are no blood vessles, no arteries, veins, nor capilarries, so the cells of the cornea are limited in the amount of nutrients they recieve to: osmosis from the sclera (which might be good for the corneal cells along the perpherie, but not along the crest), to be carried to them via the vitreous humor (the gelatinous fluid between the lens and iris and the cornea (which, by it's thick syruppy consistincy isn't all that prone to circulation, much less nutrient transport)), or the tears. So, the tears, not only carry nutrients to the corneal cells, but also carry the waste products of the corneal cells away, through the lachrymal duct into the nose (which is where most of the snot we get in our noses comes from).

Of the three types of tears, the emotional tears carry more protiens than basal or reaction tears, mainly because those tears are the tears that a baby will utilize to communicate hunger.

This is where the primates appear to differ from all the other genuses of the animal kingdom, is that whereas a puppy or a kitty will whimper and cry and the mother will come arunning to suckle them, for a relatively brief amount of time, and wheras larger quadrupedal mammals will suckle for as long as their mother doesn't just kick them away, human infants (before the advent of baby formulas) tend to be inordinately spoiled by their mothers, who tend to nurse their infants for over a year, in some cases several years.

I believe this is due to a pheromonic protein in tears that when a lactating woman either tastes it or smells it or whatever, will induce lactation, and the woman will nurse the child, sometimes even LONG after the child is old enough to be eating and foraging and/or hunting on his or her own.

All because we were either created with, or we evolved with a chemical form of communication between infant and mothers.

This chemical form of communication is never outgrown, either.

Women tend to be more 'emotional' than men, breaking down and crying at the drop of a hat at times, and men respond to it, quite instinctively, becoming a layer of protection for whichever woman it happens to be who might be shedding tears.

If a child cries for the exact same reason, be it a boy or a girl, most men will tend to ignore it, but be they the tears of a post-pubescent female, and most men will unconsciously gear themselves up to fight to the death on behalf of the tear shedder.

This, of course is part of an instinctual precursor to possible reproduction, but very few men I've ever caught becoming the instant protecter has ever really even thought about it in that way.

So, to sum it up, tears nourish the eye, cleanse the eye, protect the eye, and communicate between infants and mothers and between women and men.

Answer 3

The act of crying was first develpoped to remove foreign objects from the eye! I don't understand why we do it when we are sad or happy! Did you know though, the only other mammal which cries is an elephant?!

Answer 4

Which crap said animals never cry? They do cry...its juz d way they do it is different frm human beings....
Ok humans cry in order to let down their emotions...regardless of wheter it's bcos of happyness r sadness.....they cry......its a natural thing to do...they need to cry out in order to feel ease.....so that they'll wont feel the burden of the problem r stuffs they are facing......

tats all frm me....hope my answer helped u a bit.......Tcare....

GoDBlesS!!!

Answer 5

Animal does cry by the expression of their body language. Eleplants smell the dead bone of their kind. A young leopard or cheetah look back at their mother before leaving for their own survival. Lions smell and roar at their dead comrades. Dogs sneak noise when agony.

Bad & evil human being seldom cry. Obeserve it.

Answer 6

Sad, happy, something in the eye, anticipation, pain. Animals DO cry, just not the same way we do.

Answer 7

"Hard as it is to believe, hardly anyone studies crying. As a scientist buddy told me the other day, "It's just TOO BIG A QUESTION."
But we've never let that stop us before!
So I tracked down Paul Verrell here at Washington State University. He studies animal behavior. (He is also one of those rare scientists who is willing to SPECULATE.) Much thinking about behavior is also about evolution, because that's where much of our behavior comes from. So when Professor Verrell asks why, he asks WHY.
Let's start with the idea that crying is a form of communication. (Now keep in mind we're SPECULATING here.) In fact, it's a very young baby's ONLY form of communication. Imagine yourself, lying on your back, staring out at this very weird new world. You can't talk or crawl or even think or see very clearly. But your body says: "I'M HUNGRY."
Scientists who think about evolution think a lot about "evolutionary advantage." Basically, an evolutionary advantage helps you survive so you can pass your genes on to your descendants. And your genes aren't going to get passed on if your body doesn't get FED. So you scream!





Maybe my friend here just needs to give in to ritualization.
(The painting is Absinthe (1876) by Edgar Degas.)


Technically, if you're less than two months old or so, you're not really crying—if you define crying as shedding tears. Babies don't start crying tears until they're about two months old. But screaming gets results, and the tears get connected later.
Actually, there are three kinds of tears. BASAL tears lubricate your eyeball. Your eyeball is really not very smooth, so without tears to smooth it over, you wouldn't be able to see very sharply. Various tear glands produce about 5-10 ounces of basal tears daily. These tears flow over the eye and into the LACHRYMAL ducts in the inside corners of your eyes and then into your nasal cavity.
REFLEX tears protect your eyes against irritants, such as onions, and foreign objects or blows.
Now get this. There's a big difference between EMOTIONAL tears and these other kinds of tears. Emotional tears contain 20-25 percent more protein, including various hormones! So what does this mean? WE DON'T KNOW, BUT IT IS VERY INTERESTING.
Actually, some scientists think tears are a way for the body to get rid of wastes, as is sweating or defecation.
On the other hand, maybe crying is a functionless byproduct of increased autonomic activity in distressed individuals. WHAT?! Pat Carter is an evolutionary physiologist here at WSU. He studies how our bodies came to do the things they do over the course of time. He is very careful about trying to guess why something like crying developed. Maybe it developed as the result of something that we're not aware of.
Well, says Professor Verrell, maybe so. Still, crying would continue to exist through human evolution IF IT TOOK ON A FUNCTION. So what might that function be?
Communication!
Behaviorists call this process -- of a byproduct taking on a new function -- RITUALIZATION.
Professor Verrell compares this to a dog's peeing when it gets excited or runs into something new. Over time, peeing seems to have transformed, or ritualized, from an autonomic response into a form of communicating where its territory is.
Professor Verrell says that communication signals that have evolved through ritualization are usually stereotyped, exaggerated and repetitive. So MAYBE crying came to be because the people (babies and others) who cried hardest, longest and loudest were most likely to get food or help.
But wait! you say. You're not done yet. What about sadness and anger and grief and other reasons we cry?
We don't know. Maybe Aristotle and others long ago were right. Maybe crying is a means of cleaning yourself out emotionally. Or maybe it's your communication of last resort, the only way to express yourself when words fail, the same as when you were a baby and had no words."

Answer 8

Elephants also cry- it is not exclusively human behaviour.

Answer 9

i don't cry and i think i am a human.
i do get this weird chock in my throat....it makes me want to just slice my throat and pull the dam thing out.

Answer 10

every thing cries...............in cartoons. oops but i don't have an answer for u.