Humans should always be careful not to overly anthropomorphize animals and apply our sense of morality onto nature. That said, these otters really are depraved little jerks.
A video from a few years back shows a group of otters drowning a monkey at the Bronx Zoo in New York. The scene appears to be filmed at the zoo’s “JungleWord” exhibit, which contained both Asian small-clawed otters and Javan lutung monkeys. Javan lutungs (Trachypithecus auratus), sometimes known as ebony leaf monkeys, are a vulnerable species native to eastern Java, Bali, Lombok, Palau Sempu, and Nusa Barung.
The video shows a gang of otters smothering and drowning a panicking Javan lutung while its monkey comrades watch, screech, and attempt to save it.
It isn't clear why the otters are behaving like this or how the monkey got into the water, however things don't look too good for the unlucky primate. You can watch the video below, as well as a more zoomed out version at the bottom of the page.
The war between monkeys and otters is a long and bloody one. At a zoo in Bristol, UK, there were reports that otters killed and ate an endangered golden lion tamarin monkey after it fell into a pond.
Perhaps it’s just a few bad apples, you might say. Unfortunately, this is only the beginning of their debauchery. Otters (sea otters in this case) are known to rape baby seals to death. They are also known to hold baby otters hostage until the mother pays a ransom of food. Their depravity is only comparable to the equally cute Adélie penguin, whose cannibalistic and sexually aggressive behaviour were so shocking when originally discovered in 1912 that studies didn't publish their findings at the time.