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The Dark Secrets That Dolphins Don’t Want You to Know

Two dolphins in the water
Justin Sullivan/Getty Images

Slate’s archives are full of fascinating stories. We’re republishing this article because it remains a reader favorite. It was originally published May 13, 2009.

It never fails. Every single cocktail party, as soon as someone finds out that I’m a graduate student studying marine biology, they ask, “So, do you get to play with dolphins?” Since my heart is as black and cold as the oceanic abyss, I usually take this opportunity to disillusion yet another poor soul of their childhood fantasy of Mystical Dolphin Love .

Dolphins are not gentle or psychic. If they could talk they would not impart eco-wisdom or deep spiritual truth. Dolphins are violent predators with a predilection for baby killing and rape. I feel it’s my duty to warn you, despite the risk of insulting creatures made of hundreds of pounds of muscle and rows of sharp teeth. Throw out your rainbow dolphin painting , and check out dolphins’ low-down dirty secrets:

–Dolphin sex can be violent and coercive. Gangs of two or three male bottlenose dolphins isolate a single female from the pod and forcibly mate with her, sometimes for weeks at a time. To keep her in line, they make aggressive noises, threatening movements, and even smack her around with their tails. And if she tries to swim away, they chase her down. Horny dolphins have also been known to target human swimmers -Demi Moore is rumored to have had a close encounter of the finny kind.

–Dolphins kill harbor porpoise babies. In Scotland, scientists found baby harbor porpoises washed up with horrific internal injuries. They thought the porpoises might have been killed by weapons tests until they found the toothmarks. Later, dolphins were caught on film pulping the baby porpoises-the dolphins even used their ecolocation to aim their blow at the porpoises’ vital organs.

–Dolphins kill their own babies. Baby dolphins have washed up alongside the dead porpoises, and some scientists think that all the porpoise-slaughter was just practice for some old-fashioned infanticide . For other mammals like lions, killing the babies makes the females immediately ready for the next pregnancy, and maybe that’s the case with dolphins, too.

The scariest part is dolphins can wreak havoc day and night without sleeping. A recent study found that dolphins could stay awake for five days straight with no loss of mental acuity. The dolphins didn’t even need to make up sleep at the end of the study, though the scientists sure did.

If the dolphins ever evolve thumbs , we’re in trouble. It will be like a slasher-film remake of Douglas Adams’ So Long And Thanks for All The Fish . If I wash up with pulped innards and dolphin tooth marks, you’ll know why. After all, you never hear about the people the dolphins push out to sea.