8 arms to smack you: ‘Spiteful’ octopuses may punch fish just because they can

Life under the sea may look fun in Disney’s version of The Little Mermaid, but if you’re a hungry fish just cruisin’ for some food on the sea floor, things can get a little rough — especially if there’s an octopus with a mean streak lurking nearby.

In recently-released video accompanying a study published in Ecology, researchers were left with little more theories after witnessing seemingly malevolent octopuses taking their ill aquatic tempers out on fish that appeared to be just mindin’ their own business. It’s a behavior that scientists have known about for a while — but the new video, along with the fresh research, offers one of the best, up-close looks yet at the strange phenomenon.

Check it out:

As marine biologist and National Geographic Explorer Eduardo Sampaio pointed out in a series of tweets, there’s more going on here than our hapless fish friends simply being in the wrong place at the wrong time. Octopuses and fish often hunt alongside each other for mutual benefit in a sort of unspoken, cross-species pact. But it’s clear from the research (as well as the video) that the octopus is the alpha leader that runs the show.

For now, it appears that octopuses reach out and smack their fish frenemies for only a limited number of reasons: either they’re trying to heighten the group dynamic by keeping all their co-hunters sharp, they’re out to take the best prize, or — and this is the “spiteful” part — they’re simply exercising those tentacles because they can.

“Octopuses and fishes are known to hunt together, taking advantage of the other's morphology and hunting strategy,” wrote Sampaio. “…Since multiple partners join, this creates a complex network where investment and pay-off can be unbalanced, giving rise to partner control mechanisms.”

In other words, when you’re hunting in a pack, somebody has to take point — and in this case, it appears to be the octopus. But on some occasions, octopuses seem to exhibit the lightly aggressive behavior even when there’s no clear survival benefit.

"In these cases, two different theoretical scenarios are possible,” the study explains. “In the first one, benefits are disregarded entirely by the octopus, and punching is a spiteful behaviour, used to impose a cost on the fish.

“In the other theoretical scenario, punching may be a form of aggression with delayed benefits (i.e. direct negative reciprocity or punishment), where the octopus pays a small cost to impose a heavier one on the misbehaving partner, in an effort to promote collaborative behaviour in the following interactions.”

Either way, it’s enough to make The Little Mermaid’s Sebastian the crab drop his conductor’s wand and scuttle off to safety. But thankfully (so far as we know), no fish are actually harmed in these strange eight-legged encounters…unless, perhaps, they possess a hidden propensity for a little wounded pescatarian pride.