Do Animals Commit Suicide???
In 1845 a curious story appeared in the Illustrated London News.
A black dog, described as "fine, handsome and valuable" was reported to "throw himself into the water" in an attempted suicide. His legs and feet were in "perfect stillness" – highly unusual for a dog in a river.
Even stranger, after he was dragged out he "again hastened to the water and tried to sink again…"
Eventually the handsome dog succeeded in his apparent suicidal mission and died.
He cited 21 apparent animal suicides, including a dolphin who let himself be captured
According to the Victorian press, this dog was far from alone in attempting such a fate. Shortly afterwards, two other cases appeared in the popular press: a duck drowned on purpose, and a cat hanged herself on a branch after her kittens had died.
But what was the truth of these incidences?
We know that animals can suffer from mental health issues in the same way humans do: in particular they feel stress and get depressed, factors contributing to the act of suicide in humans. We also know that behaviours once thought to be uniquely human have now been found in other animals.
But is suicide among them? Do animals really, knowingly attempt suicide?
It is not a new question: the ancient Greeks considered it too. Over 2,000 years ago, Aristotle cited a stallion that threw himself into an abyss after it became apparent that, like Oedipus, he had unknowingly mated with his own mother.
In the 2nd Century AD, the Greek scholar Claudius Aelian devoted an entire book to the subject. He cited 21 apparent animal suicides, including a dolphin who let himself be captured, several instances of hounds starving to death following the passing of their owners, and an eagle that "sacrificed itself by combustion on the pyre of its dead master".
A wild stag, rather than be overtaken by its pursuers, will fall into the jaws of an awful death
Just like the "handsome dog" that drowned, the idea of animal suicide remained a popular topic among 19th-Century Victorians. One psychiatrist, William Lauder Lindsay, attributed "suicidal melancholia" to animals of this disposition, describing how they could be "literally goaded into fury and mania" before a suicide.
At the time, these ideas were seized upon by animal rights groups, such as the UK-based Royal Society for the Prevention of Cruelty to Animals (RSPCA). Animal activists sought to humanise animal emotions, explains medical historian Duncan Wilson, of the University of Manchester, UK, who looked into historical cases of references to animal suicide in a 2014 research paper.
They did so, he says, to show animals "shared the capacity for self-reflection and intent, which included intent to kill themselves out of grief or rage.”
For example, in the 1875 edition of the RSPCA journal Animal World, the cover depicted a stag jumping to a suicidal death. The accompanying editorial stated that "a wild stag, rather than be overtaken by its pursuers, will fall into the jaws of an awful death".
However, as medicine advanced in the 20th Century the human attitude to suicide became more clinical, and these type of "heroic portrays" of suicidal animals dwindled.
Such stories should not fool us
Instead, the focus shifted onto suicide affecting larger populations, often as a result of social pressure, says Wilson. Suicide became more of a social malady. Take the examples of the lemmings who apparently march towards cliffs and throw themselves off, or mass whale strandings.
But Wilson did not seek to answer whether animals really do attempt suicide. Instead, his work revealed that changing attitudes to human suicide were reflected in our stories about animals.
However, another researcher wanted to answer the question head on.
Such stories should not fool us, according to Antonio Preti, a psychiatrist at the University of Cagliari in Italy, who scoured the scientific literature on animal suicide.
He looked at about 1,000 studies published over 40 years, and found no evidence of an animal knowingly attempting suicide in the wild. Cases such as those in Aelian's book are "anthropomorphic fables", he says.
Researchers now know that the mass deaths of lemmings are an unfortunate consequence of a dense population of creatures emigrating together at the same time.
In cases where a pet dies following its master's death, this can be explained by the disruption of a social tie, says Preti. The animal does not make a conscious decision to die; instead, the animal was so used to its master that it no longer accepts food from another individual.
"To think it died from suicide like a person after the death of a spouse is just a projection of a style of [romantic] human interpretation."
This example points to the one important fact. Stress can change the behaviour of an animal in a way that can threaten its life.
This happened at SeaWorld's Tenerife park in May 2016.
A video went viral of a wild-born orca in one of SeaWorld's parks that appeared to beach herself on the side of the tank for about ten minutes. Dozens of articles appeared stating she had attempted suicide.
The vast majority of cases are down to human intervention in some way
We know that orcas behave differently in captivity than in the wild, which is unsurprising given that a tank is a fraction of the size of the ocean. Unnatural environments have been known to stress captive orcas, triggering repetitive behaviours such as rubbing the side of their tanks and grinding their teeth.
When it comes down to it, says Barbara King of the College of William & Mary in Virginia, US, it is important to understand just how deeply these animals experience emotions. This can in turn inform us about what causes them to act in self-destructive ways.
"To my knowledge the vast majority of cases are down to human intervention in some way, whether the result of poaching or confinement," says King, who has written extensively about animal grief and suicide.
Many other animals kept in traumatic conditions also experience conditions similar to stress, post-traumatic stress disorder (PTSD) and depression.
It can be seen as a reflection of an animal trying to escape its imprisonment
A captive bear at a Chinese bear farm was reported to have smothered her son and then killed herself. This followed an extremely painful injection of a catheter into the bear cub's abdomen to extract bile, which is sometimes used in Chinese medicine. Newspaper reports suggested she had killed herself and her son to prevent more years of torture.
This is more likely another example of unnatural behaviour triggered by stress and being housed in an artificial environment for a prolonged period of time. It can also be seen as a reflection of "an animal trying to escape its imprisonment," says Preti.
Thinking of it this way makes more sense. If animals denied the risks of death as many humans do, zebras might knowingly graze near lions, fish swim alongside crocodiles, and mice stare into the eyes of snakes.
If they were self-aware to the extent we are, they might also stop defending their territories or foraging for food. They have an appropriate in-built response to fear for good reason: it keeps them alive.
We are the only animal able to understand and cope with our own mortality, Varki argues, precisely because we are such optimistic creatures with a sophisticated level of self-awareness.
"What is suicide?" asks Varki. "It is inducing your own mortality, but how can you induce it if you don't know you have mortality? It's [therefore] quite logical that suicide should be uniquely human."