Why do only humans cry tears

I just listened to Obama’s speech on the recent mass murder and found myself crying tears from empathy.
This made me reflect on the common ability of humans to cry tears from emotion, in addition to cleansing and lubrication.
What purpose do tears serve?

However, in his new book, Why Only Humans Weep, Vingerhoets argues that none of these explanations is sufficient. Although crying has been documented in apes, elephants and even camels, it seems that only humans produce emotional tears, and it is only in humans that crying behaviours persist into adulthood. The challenge is to explain why this should be so, given that tears also run the risk of signalling our presence to predators.
http://www.theguardian.com/science/2013/apr/14/why-do-humans-cry-biology
I just listened to Obama's speech on the recent mass murder and found myself crying tears from empathy. This made me reflect on the common ability of humans to cry tears from emotion, in addition to cleansing and lubrication. What purpose do tears serve?
However, in his new book, Why Only Humans Weep, Vingerhoets argues that none of these explanations is sufficient. Although crying has been documented in apes, elephants and even camels, it seems that only humans produce emotional tears, and it is only in humans that crying behaviours persist into adulthood. The challenge is to explain why this should be so, given that tears also run the risk of signalling our presence to predators.
http://www.theguardian.com/science/2013/apr/14/why-do-humans-cry-biology
They apparently relieve tension, at least temporarily. Lois

http://news.discovery.com/animals/zoo-animals/do-animals-cry-130917.htm
Apparently, elephants do and it seems to be connected to emotion.

This is a question in which a hypothesis does not immediately come to mind, aka, “good question”.

If it is the case that both elephants and humans cry emotional tears, why is this?
Here is a hypothesis: 1st consider that elephants are among the most social of creatures in their development. http://elephant.elehost.com/About_Elephants/Life_Cycles/Baby/baby.html
Also, consider that elephant’s period of post natal brain development is long. Human post natal brain development is long.
Perhaps there is some similar neurological mechanism present in highly (developmentally) social creatures that is involved in crying tears of emotion.
Still why would this have evolved in highly developmentally social creatures? Perhaps it is a part of the same neurological processes that make complex verbal behavior an integral function in such creatures. (Land creatures, anyway. I don’t suppose dolphins shed emotional tears. Or maybe they do, and that is where the oceans come from… Just kidding.)

Perhaps humans value human life more than other species value the life of their species. I hypothesize that the ability to value a wide variety of things, this is a categorical and mathematical function, over time is the essence of differentiation in human consciousness over animals.
Isn't it more a matter of humans being aware of death. I started that sentence, that humans are the only species aware of their own mortality, but how do we know. The heartbreaking chimpanzee mom holding on to her dead child for days, elephants and now I found this article that adds a few new ones. http://www.care2.com/causes/4-animals-who-mourn-their-dead.html I agree with you that it's probably more a matter of degrees, than any unique human threshold. We are simply capable of comprehending so much more of the world and our own lives.
Isn't it more a matter of humans being aware of death. I started that sentence, that humans are the only species aware of their own mortality, but how do we know. The heartbreaking chimpanzee mom holding on to her dead child for days, elephants and now I found this article that adds a few new ones. http://www.care2.com/causes/4-animals-who-mourn-their-dead.html I agree with you that it's probably more a matter of degrees, than any unique human threshold. We are simply capable of comprehending so much more of the world and our own lives.
Interesting CC, but we can differentiate between a sentient creature being aware of "mortality" and being aware of their own mortality. Having said that, It's possible that chimps are aware of their own mortality. Who knows? Actually fight or flight is ingrained and that would be a definite pre-cursor if you will. That's a stretch. But the hardware is ingrained to avoid death. How far this translates into an advanced consciousness is questionable. ie..aware of own mortality. It wouldn't surprise me if other primates or other mammals had this....but it's still a stretch. I got a feeling they're gonna figure this out though.

I wonder if crying is related to the sense of loss
"we cry for that which was once our delight* , Kahlil Gibran

Now that John Boehner has more free time, he could be an excellent subject for research in this matter.

Crying is seldom voluntary. We cry when we can’t help ourselves. It creates an emotional release. It may even be an evolutionary advantage.
Lois

Crying is seldom voluntary. We cry when we can't help ourselves. It creates an emotional release. It may even be an evolutionary advantage. Lois
From the perspective of the mirror neural network you may be right. When we see someone cry (even as we don't know the cause), our MNN always triggers a feeling of empathy. We *know* that person has experienced a traumatic episode and is mentally suffering. We even cry watching a *good* drama in theatre or even tv. That is very sophisticated MNN processing. But I am sure, you are right that it must be a form of emotional release, perhaps even sharing. But sometimes we "laugh to the point of crying". Extreme emotions of Joy or Sorrow resulting in crying. Now is'nt that ironic?

And there is always the;

Pseudobulbar affect (PBA), emotional lability, labile affect, or emotional incontinence refers to a neurologic disorder characterized by involuntary crying or uncontrollable episodes of crying and/or laughing, or other emotional displays

https://en.wikipedia.org/wiki/Pseudobulbar_affect

Crying is seldom voluntary. We cry when we can't help ourselves. It creates an emotional release. It may even be an evolutionary advantage. Lois
From the perspective of the mirror neural network you may be right. When we see someone cry (even as we don't know the cause), our MNN always triggers a feeling of empathy. We *know* that person has experienced a traumatic episode and is mentally suffering. We even cry watching a *good* drama in theatre or even tv. That is very sophisticated MNN processing. But I am sure, you are right that it must be a form of emotional release, perhaps even sharing. But sometimes we "laugh to the point of crying". Extreme emotions of Joy or Sorrow resulting in crying. Now is'nt that ironic? Emotions other than sadness or loss can trigger a physiological response--tearing. So can dust in our eyes or a cold or allergies, which have nothing to do with emotion.
Now that John Boehner has more free time, he could be an excellent subject for research in this matter.
That's low. Now I gotta clean the coffee off my laptop. :lol:
Crying is seldom voluntary. We cry when we can't help ourselves. It creates an emotional release. It may even be an evolutionary advantage. Lois
From the perspective of the mirror neural network you may be right. When we see someone cry (even as we don't know the cause), our MNN always triggers a feeling of empathy. We *know* that person has experienced a traumatic episode and is mentally suffering. We even cry watching a *good* drama in theatre or even tv. That is very sophisticated MNN processing. But I am sure, you are right that it must be a form of emotional release, perhaps even sharing. But sometimes we "laugh to the point of crying". Extreme emotions of Joy or Sorrow resulting in crying. Now is'nt that ironic? Emotions other than sadness or loss can trigger a physiological response--tearing. So can dust in our eyes or a cold or allergies, which have nothing to do with emotion. The chemical composition of emotional tears is said to be quite different than lubricating and allergy produced tears. It is said that the chemicals released with emotional tears may result in physiological benefit for the individual. Look it up.
Now that John Boehner has more free time, he could be an excellent subject for research in this matter.
That's low. Now I gotta clean the coffee off my laptop. :lol: Thank goodness for the rare individual who can appreciate my attempts at humor. (I hope your laptop is ok.)
Now that John Boehner has more free time, he could be an excellent subject for research in this matter.
That's low. Now I gotta clean the coffee off my laptop. :lol: Thank goodness for the rare individual who can appreciate my attempts at humor. (I hope your laptop is ok.) Oh yeah, I learned long ago to keep a keyboard plastic cover on the thing. Miss MacII is just fine thank you very much.
Crying is seldom voluntary. We cry when we can't help ourselves. It creates an emotional release. It may even be an evolutionary advantage. Lois
From the perspective of the mirror neural network you may be right. When we see someone cry (even as we don't know the cause), our MNN always triggers a feeling of empathy. We *know* that person has experienced a traumatic episode and is mentally suffering. We even cry watching a *good* drama in theatre or even tv. That is very sophisticated MNN processing. But I am sure, you are right that it must be a form of emotional release, perhaps even sharing. But sometimes we "laugh to the point of crying". Extreme emotions of Joy or Sorrow resulting in crying. Now is'nt that ironic? Emotions other than sadness or loss can trigger a physiological response--tearing. So can dust in our eyes or a cold or allergies, which have nothing to do with emotion. The chemical composition of emotional tears is said to be quite different than lubricating and allergy produced tears. It is said that the chemicals released with emotional tears may result in physiological benefit for the individual. Look it up. I know, but I don't usually have my lab equipment handy when I witness someone tearing up. :) Lois

It may be tears in emotional situations may have evolved as a signal of one’s distress to others of our species. We are a cooperative species.

It may be tears in emotional situations may have evolved as a signal of one's distress to others of our species. We are a cooperative species.
Yes, quite possible. But, if it is true that elephants also have emotional tears, are we to conclude that elephants are an equally (or substantially so) cooperative species? And, if so, why did emotional tears not evolve in other cooperative species? Also consider that we also cry when there is no one around to notice. Might it also be a kind of fail-safe "modulation of emotions" system, that is important for creatures who rely more on reasoning for survival than on pure emotions? (Still there is the quandary of other species who do and don't have emotional tears, and why that is. This might be resolved by discovering that elephants have an undetected system of verbal behavior that rivals that of humans in its sophistication. But that seems like a pretty far out hypothesis.)