Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Medical Suicide: Why is it so rare among species?

  1. Sep 30, 2010 #1
    I was looking at some global suicide statistics and I think it's an interesting question.

    Especially if you look at it what motivates suicide. There is nothing intrinsic that gives humans and most species, the desire to end life. It seems as if external factors are the main cause--mental disorders, personal troubles (ie financial, marital, problems). But there is nothing comparable to hunger, thirst, mating, sleep, etc.--in terms of ending life.

    According to the stats, On average, almost 3000 people commit suicide daily. For every person who completes a suicide, 20 or more may attempt to end their lives.

    Even one million people successfully committing suicide per year, is an incredibly small percentage.

    I guess from an evolutionary viewpoint, we do what we can to stay alive. It would be irrational for us to leave. Even solar nebulae, from an entropic viewpoint, don't have the option of not forming a solar system. But almost all species do have that choice and yet, choose no. There isn't that much data on animal suicide. But I have heard of scorpions stinging themselves when surrounded by fire.

    I thought this was an interesting question, anyone else agree?
  2. jcsd
  3. Sep 30, 2010 #2
    Only human beings understand mortality. When a cat sees another cat that is dead, it doesn't like it and it wants to get away, but it isn't made to contemplate its own mortality. There is, I believe, some evidence of elephants engaging in a behaviour that suggests something like genuine mourning for a lost member of the herd, but that doesn't mean that they thus contemplate their own mortality. It has been suggested before that it was evolution's most tragic accident that humanity ever became intelligent enough to understand its own fate. And it was out of that tragedy that the need for religion came.
  4. Sep 30, 2010 #3


    User Avatar
    Gold Member

    Are you implying that the violinist who jumped off the George Washington bridge had a mental disorder and it was his homosexuality? :biggrin:
  5. Sep 30, 2010 #4
    Where did you see a choice? Ever saw a happy person suicide?

    Hmm, no... Just do a research.
  6. Sep 30, 2010 #5
    I'm not so sure about that. I would like to know why the antelope avoids being eaten. Yes, perhaps it is to avoid the pain--not knowing anything about death.

    Like I mentioned before, there isn't much on animal suicide. But take a look at this little bit I got off wiki:

    Suicide has been observed in salmonella seeking to overcome competing bacteria by triggering an immune system response against them.[107] Suicidal defences by workers are also noted in a Brazilian ant Forelius pusillus where a small group of ants leaves the security of the nest after sealing the entrance from the outside each evening.[108] Pea aphids, when threatened by a ladybug, can explode themselves, scattering and protecting their brethren and sometimes even killing the lady bug.[109] Some species of termites have soldiers that explode, covering their enemies with sticky goo.[110][111] There have been anecdotal reports of dogs, horses, and dolphins committing suicide, but little hard evidence.[112] There has been little scientific study of animal suicide

    Luckily, I read about this tragic story after I had started this thread and before I saw your post. So it's a good thing I'm informed, otherwise I'd have no idea what you meant.

    But no. His problem had nothing to do with a mental disorder. Although, it was due to external forces. Had those people not embarrassed him by broadcasting his escapade on the internet, he most probably would not have chosen to take his life.

    No. But that's exactly my point. A happy, rational person would not commit suicide. But that person does have the choice. And intentionally chooses not to. Why do we instinctively choose life, when that option is readily made available to humans. I can understand an animal, not having the capability of self-awareness.
  7. Sep 30, 2010 #6


    If you explain the nature of your objection to my assertion, I can respond to it. In the face of such a pointless comment I have no response to offer.

    I don’t suggest that the antelope runs from a predator because of fear of pain. It runs because it feels a fear it is genetically programmed to feel. That doesn’t mean that it has any cognitive understanding of mortality. There is a much more subtle point I could make in support of this but I haven’t time now. I’ll perhaps return and expand on this point later.
  8. Oct 1, 2010 #7
    I don't agree. I don't think humans understand mortality at all.
    An identity is a very murky thing.
    Don't misunderstand me I am not implying that there is anything after death (far from it) ; I am saying that simply having an identity obscures the truth of mortality.

    Merely having one is like a hall of mirrors.
    For example : If you are thinking of yourself... which part of yourself is doing the observing? Who is observing the observer? When a person is unstable how can they understand that their death and it's consequences mean total annihilation? It is hard to grasp that concept even when thinking rationally.

    I think many who kill themselves become clouded in understanding that when they die, the observer within them (their personal narrator of their life's story) dies too.
    Last edited: Oct 1, 2010
  9. Oct 1, 2010 #8


    User Avatar

    Staff: Mentor

    If you have a scientific source for that behavior, please post it. Instead, I found this:


  10. Oct 2, 2010 #9
    here we go again. we always assume or start by assuming that we are different from our cousins in the wild ( animals ). Then 80 years later we discover that we are not in fact very different. Who can say with certainty that whales beaching themselves is not suicide?

    "And it was out of that tragedy that the need for religion came."

    hum, I must be different, I have never felt any need for religion. Food, sex, warmth yes but not religion.
  11. Oct 2, 2010 #10
    I wasn’t really making some deeply philosophical point about how well we understand the nature of life and death. Clearly, every reasonably intelligent adult human being understands the bald reality that one day they will die. They understand the inevitability of that fact whether or not they understand the true nature of life and death. We all understand that all life is mortal, that anything that lives can die, and thus that suicide is something that is possible. It is that very basic understanding that human beings have and no other species has.

    And yes, since we are in that subject area, let me be the one to raise it. Hamlet’s famous speech. The key profundity in it, it seems to me, is the point that if we all knew that what came next was something better, we’d all be committing suicide left, right and centre. It is only the uncertainty about what comes next that holds us back and makes us endure all the struggles of ‘the human condition’. That’s a pretty bleak view of life, but hey, the guy was under a lot of pressure.

    I’m not sure if it is really of much consequence, or if people will understand the relevance to my point, but here’s that point I was thinking about in post #6, regarding how animals can sometimes appear to possess a degree of understanding that they don’t actually have. It was in something I read that was talking about the whole business of language, and whether or not that is something unique to human beings. There are species that have a capability to give different warning signals to their group mates according to the nature of an impending threat. So, for example, it might be a species of primate that generally operates at ground level, but lives near trees. If one of the group sees a snake it will give one very specific signal, and they will all flee to the trees. If one of them sees an eagle, it will make a completely different signal, and they will all take cover under the trees at ground level. Specific signals for specific threats and specific reactions appropriate to those signals – it has to be language, right? Wrong. It is perfectly possible for that species to have evolved a genetically programmed behaviour to give the snake signal if it sees a snake, and the eagle signal if it sees an eagle. Quite separately, it can also have evolved the genetically programmed behaviour to react to the one signal by heading for the tress and to the other by heading for cover. No intelligent cognition of ‘that’s the signal for a snake, I need to get high’ or ‘that’s the signal for an eagle, I need to take cover’ ever takes place, and nothing resembling language takes place either.
  12. Oct 5, 2010 #11
    Because natural selection selects against it.

    Natural selection favours the specimens within a species that desire to live.

    How do you know it is a fear the antelope feels that makes it run? Is it not simply "genetically programmed to [STRIKE]feel[/STRIKE] run from a predator"?

    Can't we just as well argue the same for humans, they are just genetically programmed to do the things they do?
  13. Oct 5, 2010 #12
    There was an experiment done decades ago involving rats living within a confined space. It was initially populated by a genetically diverse group of twenty-thirty rats. Their "city" was a rather large space, and they had plenty of food and water, and it was kept clean.

    They were allowed to breed without check.

    They quickly reached population saturation in the first year, after which the number of births dropped sharply, so that the population remained stead for the middle year of the experiment. About halfway through, however, more and more of the rats began exhibiting strange behaviors, including excessive preening, not cleaning themselves at all, over-agression, and being overly timid.

    About 18 months into the experiment, their numbers began to decline, and by the two year point, there were no longer any rats living at all!

    I see similar behaviors in humans today, but not all humans. Just some. As for the population decline to extinction, it wasn't due to physical disease. I don't know whether it was due to overcrowding leading to depression and a lack of will to mate, lack of predators (a decisive, but quite natural environmental pressure), or what.

    The point is, left unchecked, when population densities grow well beyond normal bounds, strange things begin to happen!
  14. Oct 5, 2010 #13
    Well gerben, I suppose that the premise from which I start is that human intelligence is of a whole different order from that of any other species. Yes I have seen demonstrations of some of the extraordinary abilities of some species; squirrels that can solve complicated logical puzzles; pigeons that can be taught to discriminate between the works of different painters such that, even when they are shown a painting they have never seen before they know the appropriate response they have been trained to give for that painter; chimps that are capable, not just of complex social interactions with each other, but of really quite sophisticated interactions with human beings; and dolphins, just quite what dolphins are capable of could fill a thread of its own.

    I recall seeing a demonstration of just how simple a creature crocodiles are. Almost all of their behaviour is purely instinctive. Domestic cat and dog owners will all tell you that there is nothing the least bit anthropomorphic in recognising that such animals are capable of a level of spontaneous decision making that perhaps crocodiles are not.

    But it is a vital point to understand that none of these things mean that these species have anything like the cognitive abilities of human beings. I’m going to make reference to a book I’ve mentioned before – ‘The Origins of Life’ by John Maynard Smith and Eörs Szathmáry. It identifies seven major transitions in evolution when significant developments led to a sudden broadening of the future possibilities. The last of the transitions they identify is the development of language. With reference to a British archaeologist named Steven Mithen, they identify three distinct types of intelligence that existed in our ancestors before the development of language; a social intelligence – the ability to operate in social systems for mutual benefit; a technical intelligence – the ability to make use of available materials with purpose, the thing I suppose we would normally call ‘ingenuity’; and an intelligence for what they call ‘natural history’ but by which they do not mean anything to do with recording the past or even classifying plant and animal types, only an ability to hunt and to forage for sustenance. The key point of insight is to understand that these different intelligences were entirely unconnected. Though individuals may possess all three capabilities in significant regard, they lacked the ability to connect them in any way. That is, until they developed a fourth type of intelligence – that for language. And the point about language intelligence is that it was not just a fourth independent, unconnected intelligence, It actually grew out of social intelligence, but it served to break down the barriers between the other types of intelligence to make a truly unified intelligence, and the opportunity for rapid further development was opened up.

    So, trying to come back to your challenge to me, surely it is clear that when any prey is attacked by a predator it displays plenty of evidence of being in a state of extreme stress. Not just because it runs, but because of its wide eyes, panicky breathing, plaintive noises, surely we can all recognise these things as signs of extreme fear. But that doesn’t mean the animal has any genuine understanding of death. And it certainly can’t follow the complex cognitive chain that would be required for it to contemplate a deliberate act intended to end its own life.
  15. Oct 5, 2010 #14


    User Avatar
    Science Advisor
    Gold Member

    Actually with some study, we recognize these things not as fear, but as innervation from the sympathetic nervous system--That "fight or flight" response. Extrapolating similarities in physiological changes (the result of shared ancestry) to similarities in emotive interpretation (something our brains don't share with antelopes) is quite the anthropomorphic stretch.
  16. Oct 5, 2010 #15
    Those are all outside characteristics. When we notice them we may contribute to the animal certain feelings and emotions that we assume we would have when displaying similar characteristics. Such contributions may be correct or not and I guess we all have our own opinions about it.

    I guess I also do think the antelope feels fear though, but I also think vervet monkeys feel fear when they hear the "eagle" distress call and while they are hiding below the bushes I assume they will also have a certain "conception" of what they are afraid of. How detailed their conception of the object of their fear is I would not want to speculate on but perhaps something as "a large gliding shadow in the air". I imagine such a conception might arise because of their nervous system activating certain search templates of eagle-like shapes in order to quickly spot the danger.
    Anyway, the way in which their nervous system responds to the distress call gives the call a certain meaning, very similar to how words used by humans get their meaning.

    On the topic of suicide among animals, when a human commits suicide it is very much like fleeing from danger, from pain, from stress or basically from a situation they do not want to be in. I guess I agree with you there that humans just see an extra possible way out of the misery, a way that other animals may not be able to conceive of.
  17. Oct 5, 2010 #16
    Cats and dogs don’t commit suicide. Unfortunately and most sad, humans do commit suicide. The U.S. National Library of Medicine, U.S. Department of Health and Human Services National Institutes of Health - Medline Plus has stated on October 4, 2010 the following:

    I think it is important to learn. I'm going to take advantage of this opportunity to share what humans should be aware of so that they can help theIr own species. Information is a valuable tool! Here is an excerpt from Suicide in the U.S.: Statistics and Prevention though I encourage people (humans) to read the entire website page. Thanks.

    Last edited: Oct 5, 2010
  18. Oct 5, 2010 #17
    I've had three suicides in my direct family. My father, my mother, and my sister. My friend's roomate also commit suicide. I have also heard plenty of suicide stories first hand from people who mourned the passing of my father.

    Although it seems to run in my family I do not accept that there is genetic determinism at work and I do not think a human commiting suicide has any parallel with animals.

    I think that with the exception of euthanasia (which many don't accept as a type of suicide) suicidal people have a distorted view of themselves and their lives and that is core to the problem.

    It is also what seperates humans from other animals.. a complex sense of ourselves that can often be incorrect. Not seeing the forest for the trees so to speak.
  19. Oct 5, 2010 #18
    I do not think anyone is implying that. Speaking for myself, I was just implying that people might, in certain, occluded, situations come to see that killing themselves is a way out of a situation that they view as being unbearable... (whereas other animals may lack the cognition to come up with such a possible way to end their pain).

    It requires a certain amount of cognition to have:
  20. Oct 9, 2010 #19
    A happy, rational person will desire his happiness to continue. Otherwise he is at least not rational if not insane. And choosing death instead of continuation is only rational if the person believes in better afterlife. I'm not aware of a religion that does not forbid suicide, thus closing this door. Sure there are some suicidal cults, but I don't think the people willing to listen and believe them could be considered rational. And rational people that are not religious either do not believe in afterlife or do not know if the afterlife will be better place to be.

    So, a happy, rational person do not really have that choice.
  21. Oct 11, 2010 #20
    What about suicides by people with terminal illnesses? Sure we can determine that they probably are depressed from the illness and medications they are on but is it really all that irrational still, if they are going to die regardless - they don't need to believe in an afterlife, but they are at least certain enough that it will be less painful than what they are experiencing.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook