In the Red Sea, researchers studying fish and octopuses that hunt in teams have captured a bit of animosity between the collaborating predators on film. In a series of videos, the eight-armed invertebrates can be seen sucker punching their finned teammates with balled up arms, reports George Dvorsky for Gizmodo.
In a series of tweets about the new research, published earlier this month in the journal Ecology, lead author Eduardo Sampaio of the University of Lisbon explains that octopuses and fish are known to hunt in tandem, each making use of the other’s unique skills to flush out and capture prey. "Since multiple partners join, this creates a complex network where investment and pay-off can be unbalanced, giving rise to partner control mechanisms," writes Sampaio.
We have seen octopus in the Pacific Ocean boxing reef fish during the @globalfinprint project. This one is from Palau, but observed in other locations as well. They look to be guarding the bait bag (which one is holding on to). @LeanneMCurrey @aims_gov_au @jcu @peclabfiu pic.twitter.com/TzkKEKz21A— Colin Simpfendorfer (@SharkColin) December 20, 2020
Some of the underwater blows appeared to confer benefits to the aggressor, like getting unfettered access to food, but Sampaio also notes that there were instances where taking a swing at a nearby fish didn’t appear to provide the octopus with any apparent advantages.
Other researchers even replied to Sampaio’s post with videos of their own, documenting other pugilistic cephalopods around the world.
Between 2018 and 2019 Sampaio and his co-authors recorded a total of eight instances of octopuses punching the fish they were hunting with in Eilat, Israel, and in El Quseir, Egypt, reports Mindy Weisberger for Live Science. In an email, Sampaio tells Live Science that when he first witnessed the behavior he laughed out loud, and almost choked on his regulator.
This isn’t the first time octopuses have been observed throwing jabs at other sea creatures, but Sampaio also tells Live Science that his research represents the first scientific description linking the behavior to collaborative hunting.
Per Gizmodo, the octopuses (Octopus cyanea) unleashed their ire on a variety of fish species, including tailspot squirrelfish, black tip, yellow-saddle and Red Sea goatfishes. After getting punched, “the fish would get pushed to the edge of the group, or would actually leave the group,” Sampaio tells Live Science. “Sometimes after a while it would return, other times it would not return at all. The octopus would leave the fish alone after displacing it.”
The researchers think the octopuses are likely beating up on these fish to jockey for position in the hunting party or compete for the tastiest morsels of food, reports Peter Dockrill for Science Alert.
But in two cases, the octopus’ strikes didn’t seem to provide any obvious short-term benefits like access to food. In the paper, the researchers suggest a pair of potential explanations. “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.” The second explanation suggests “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."
Of course, with only this initial study describing the behavior we can’t know whether the octopuses are being mindlessly aggressive, bossy or calculating and strategic. For now, we’ve got the videos and, as Dvorsky writes for Gizmodo, there’s something oddly satisfying about watching the fish get walloped.