The YouTube video of a dolphin masturbating with a decapitated fish is disturbing, shocking and will put you right off your dinner.

The person who uploaded onto YouTube obviously intended such a reaction, hence the eerie carnival waltz that accompanies the self-love.

But should we be so unsettled by this video?

There’s something interesting about our revulsion which illuminates our complicated relationship both with animals and sex.

Arguably one of the main reasons this video disturbs is because the dolphin’s penis looks so, well, human. We find this similarity strange. We like to think of ourselves as separate from animals, better even.

Actually the male dolphin’s private parts have far more bells and whistles. Dolphins have retractable prehensile penises that can swivel and can be used to feel things a bit like an extra hand (those jokes about a third leg? Well they might just be relevant here).

Dolphins are also known to have a ravenous sex drive, to the point where they are thought to spend about three months in sexual play in the wild. Like humans, they have sex for pleasure, not just to reproduce. And if they are stressed, they go off sex.

We like to think of ourselves as stronger than giving in to our animal urges. ‘What separates us from the animals’ is a subject that tortured philosophers and theologians alike. Masturbation reduces us to beasts, in pure pursuit of our own pleasure.

Immanuel Kant, an 18th century philosopher came up with exactly this argument. He ultimately concluded that the immorality of masturbation lay in the fact that 'a man gives up his personality … when he uses himself merely as a means for the gratification of an animal drive'.

Self-pleasure has such historic ties to human morality, a set of values tied very much to our society, it seems strange to watch an animal do it.

But it's a rather contradictory feeling to have. We like our animals anthropomorphic as long as they are packaged correctly. We find it awe-inspiring when a dog waits by his master’s grave, when elephants cry and when the hare buys the bear a John Lewis alarm clock. Yet we really don’t like them to have sexual urges. The dog is sent out the room when it starts masturbating, lest it makes the company uncomfortable.

Of course there’s also the fact the dolphin is masturbating with a dead headless fish. Seems rather tasteless and brutal. Indeed it is. But do you know what the first condoms were made out of? In China they were, among other things, made out of lamb intestines. Renaissance condoms were made out of intestines and bladder. In the late 15th century, Dutch traders introduced condoms made from “fine leather” to Japan. Those men weren’t so bothered about using a dead animal to further their pleasure (although granted, it’s not the quite the same).