The evidence for animal suicide

Five-minute read

Can animals kill themselves on purpose? It’s a difficult question to definitively answer. I personally believe they can, but you might disagree. That’s okay. But if you’re curious to know why I’m so certain, keep reading.

I studied marine biology and animal behaviour at university. I’m by no means a world-renowned expert, but I probably understand animals better than the average person. I believe that’s the saddest flex in history.

Maybe you’re already on board with the idea. After all, lemmings are famous for their habit of throwing themselves off cliffs to their death. We’ve known about that since the 1950s.

Slight problem with that one. It’s completely untrue. The theory that lemmings undertake a gruelling mass migration then hurl themselves to their deaths in a fit of hysteria is a total fabrication of the man behind every problematic childhood belief we all cling to, Walt Disney.

The whole lemming thing comes from a documentary called White Wilderness released in 1958. Today, we all love a good wildlife documentary. But you might not realise quite how much can be staged, or even sneakily done in a studio or in captivity.

I only have once source on this, but I have been told by a wildlife documentary maker that in general, the scripts are written before they capture the footage. They plan out the narrative, then they get it on tape.

it was much worse in 1958. Disney made up a whole fake storyline for lemmings in their documentary before facing the challenge of getting his wilderness fan fiction on film.

I’d like to quote this article I found by Riley Woodford of the Alaska Department of Fish and Game in 2003 regarding how the sequence was shot -

The lemmings supposedly committing mass suicide by leaping into the ocean were actually thrown off a cliff by the Disney filmmakers. The epic "lemming migration" was staged using careful editing, tight camera angles and a few dozen lemmings running on snow covered lazy-Susan style turntable.

In fact, lemmings aren’t even native to that region. The team bought the lemmings and released them into unfamiliar territory before purposely chasing or throwing them off a cliff and obliterating them for a movie.

So that’s lemmings firmly crossed off the list. But I wish I didn’t have quite so many examples that do support my case. A good chunk of this is anecdotal evidence, but that’s bound to be the case when we’re dealing with something so difficult to prove outright.

Oh, and it’s going to be horrible. But you’re the one that clicked on a blog post with the title ‘The evidence for animal suicide’. I don’t know what you expected.

You might be surprised to learn that there are a good handful of insects that voluntarily give up their lives. Many social insect species will sacrifice themselves for the good of the colony.

Pea aphids can literally make themselves explode if a ladybird comes at them. Other aphid species patch holes in the colony walls by generating sticky secretions that also drains the life from their bodies.

Then we have parasites that mess with the host’s mind so much that it engages in suicidal behaviour, but we can’t really count those. There’s a parasitic worm that can make animals seek out their own predators so that it can move to a new host higher up the chain. It’s horrific, but it doesn’t fit the definition of suicide.

There’s an old case from 1845 that was published in the Illustrated London News. It described a Newfoundland dog that had suddenly been overcome by seemingly suicidal urges. Here’s how they put it -

To throw himself in the water and endeavor to sink by preserving perfect stillness of the legs and feet.

The dog was rescued repeatedly but broke free every time and rushed back into the water and sank underwater without putting up a fight. It did eventually drown. Dogs can also refuse food after the death of their owner, though it’s hard to say whether or not they understand the implications of their behaviour.

I need to make an important distinction here. The insects I talked about are in a different category to dogs. It’s not an intelligence thing or a mammal vs invertebrate deal. Dogs are domestic animals.

When an animal is domesticated, it changes. A long time ago, humans took wild animals and kept them captive. Soon they realised they could breed these animals selectively.

The animal that went on to become the domestic cow was the auroch. This beast was taller than the average human. Its horns were 80 centimetres long (31 inches) and could be as thick your handspan.

Over time, the smaller, more docile animals were the ones used to breed new babies that would be more manageable than their parents. Over thousands of years, the result can be unrecogniseable from its wild origin. That Newfoundland was once a wolf.

When humans interfere with animals like this, that’s when the problems tend to occur. Tarsiers are small nocturnal primates that don’t tend to live very long in captivity. They get so stressed out that they beat their heads against hard surfaces and can die as a result. I don’t know what else you could call that other than suicide. All because of human interference.

The final example nail in this coffin of a blog post is dolphin suicide. I dedicated a whole episode of my audio documentary series A Dolphin Pod to this subject, but in case you haven’t heard it or want a refresher let me go over it again.

The trainer of TV’s Flipper dolphins, Ric O’Barry reports seeing dolphins intentionally drown or beach themselves when being hunted by Japanese fishermen who intend to either slaughter them or sell them into captivity. He says it happens with multiple dolphins every year, because it’s sadly an annual practice. Not for a single day, but six or more months out of the year.

But can you prove that’s suicide? I reckon so. Dolphins aren’t automatic breathers like we are. We can forget about breathing, although we’re all on manual mode now we’re thinking about it. But we’ll self-automate again soon enough.

Dolphins can’t forget. They are air-breathers that live under water. If they forget about breathing it’s game over. They drown. It only takes a tablespoon of water to drown a dolphin. They are hot on it with their blowholes.

They’ve sacrificed sleep in the quest to stay alert enough to come to the surface at least every 15 minutes of their entire lives. They only rest half the brain at a time so they're always at least a little bit awake. It sounds like hell, but that’s their deal. They are in total control over when their blowhole opens.

I would like to present the three most famous cases of suspected dolphin suicide. The first was a male bottlenose part of a science experiment called Peter. After the study concluded he was observed to open his blowhole underwater and subsequently died very shortly afterwards.

One of Ric O’Barry’s Flipper dolphins, Cathy, did the exact same thing. As did a bottlenose named Dolly at a theme park Floridaland. In all three of those cases, the deaths followed a separation from their closest human connection. Not that they just love humans. The dolphins I’ve names were all kept in isolation for long periods. As an extremely social species, that’s torture for a dolphin. Losing the only connection they had was too much to bear.

This is not natural behaviour. These animals died because they were subjected to the torture of captivity. They evolved to swim hundreds of miles a day in the company of their choosing, not be trapped in a tank with the same few terrified others. And like I said, we know dolphins are always in charge of their breathing. It’s a choice. They chose to stop.

As I’ve mentioned roughly 11,000 times by now, we still can’t be 100% certain. Without the ability to communicate with the animals themselves, we can only review the evidence and draw our own conclusions.

I have mine. What’s yours?