Wednesday May 30 is World Otter Day, a day where your newsfeeds will undoubtedly be filled with cutesy photographs of fuzzy little otters juggling stones or holding hands while they sleep.

But don’t be fooled by this PR campaign. Behind those beady eyes lies a dark secret: Otters are assholes. It’s often pointed out that humans would be foolish to apply their moral compass onto nature; however, seriously, otters are total jerks.

Not convinced? Here’s a brief look at the mass of evidence against these sadistic, semiaquatic sickos.

Forced Sex

For starters, violence and aggression is the norm for sea otter mating, with males regularly seen holding females' heads underwater, biting their faces, and forcing them into submission. One study found that a considerable portion of southern sea otters die as a result of trauma from their hyper-aggressive sexual culture. It’s also not unheard of for the males to force themselves onto pups who have not yet reached sexual maturity.

Forced Interspecies Sex

They don’t just stick to their own species, either. As documented by a study in Aquatic Mammals, there are also numerous reports of male sea otters having violent "forced copulation” with baby harbor seals. Using a similar method of biting and drowning, the young seals often die as a result because the encounters are so aggressive. Equally, the difference in size between the two animals means they can suffer from internal perforation.

 

Necrophilia

As if that wasn’t grim enough, sea otters will occasionally hang on to a dead otter and continue to rape its corpse.

As the study above notes: “In one prior report on breeding-associated mortality, a tagged territorial male sea otter held a struggling female underwater until her body became limp and then copulated repeatedly with her carcass. Ten months later, this same male was observed with the carcass of another female sea otter. In both cases, the male was swimming, diving, guarding, and copulating with the carcass.”

Giant Not-So-Cute Otters

When you picture an otter, you probably think about the fluffy-faced sea otter or the puppy-like river otter, but there are at least 11 other species of this animal. The most terrifying of which is the giant otter of South America (pictured above), a species that will probably keep a very low presence on World Otter Day. 

These ferocious-looking beasts can grow up to 1.7 meters (5.6 feet) from snoot to toe, with hands the size of a human palm. They hunt in packs and live almost exclusively on a diet of meat, including fish, crabs, turtles, snakes, and caiman.

Sure, they are pretty cool animals, but they are also totally and utterly terrifying.

Murderous Mobs

You might try to convince yourself and think, “well, many animals exhibit pretty horrific sexual behavior,” whether it's our own closest cousin the chimpanzee or the uber-cute Adélie penguin. However, otters are one of a select few creatures who appear to relish in the killing of other animals.

 

The Bronx Zoo in New York learned that the hard way in 2016 in their “JungleWord” exhibit, which contained both Asian small-clawed otters and Javan lutung monkeys. As shown in some grainy smartphone footage, one of the small monkeys goes too close to the water’s edge and is dragged in by a gang of otters. The otters then began to smother and drown the panicking Javan lutung until it died. There were similar reports at a zoo in the UK when otters killed and ate an endangered golden lion tamarin monkey after it fell into a pond.

Otters Can Make Humans Very Sick

Granted, violent otter attacks on humans are almost unheard of. However, it seems that their weapon against humans is much more subtle and sinister.

Valley Fever is a particularly unpleasant condition that can cause fevers, brain and heart inflammation, joint pain, skin ulcers, abscesses, and bone lesions. It’s caused by a pathogenic fungus, Coccidioides immitis, that harbors in soil and – you guessed it – southern sea otters.

While otter-to-human infections are rare, professionals working with wildlife have been warned about this biological weapon.