New footage shows octopuses punching fish - yep, literally punching them - which researchers say was out of spite.
Biologist Eduardo Sampaio, co-author of research paper 'Octopuses punch fishes during collaborative interspecific hunting events', shared the montage video on Twitter, writing: "Octopuses punch fishes. YES. OCTOPUSES. PUNCH. FISHES!!"
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The team of scientists are from the Marine and Environmental Sciences Centre of the University of Lisbon in Portugal.
For the study, published by the Ecological Society of America, they filmed the octopuses between 2018 and 2019, in waters off the coast of El Quseir, Egypt and Eilat, Israel.
Sampaio said the 'punches' his team explored appeared to be motivated by practical gain - including incidents such as stealing prey off a fish.
However, in some cases, the octopus seemed to throw a punch to 'impose a cost' on 'misbehaving' fish, comparing the emotion to that of spite in humans.
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Octopuses and fish often hunt together, using each other's hunting techniques to their own advantage, but it is rare to see the former actively punch the latter.
Sampaio explained: "Octopuses and fishes are known to hunt together, taking advantage of the other's morphology and hunting strategy.
"Since multiple partners join, this creates a complex network where investment and pay-off can be unbalanced, giving rise to partner control mechanisms."
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He continued: "We found different contexts where these punches (or directed explosive arm movements, if you want to get technical about it) occur, including situations where immediate benefits are attainable, but most interestingly in other contexts where they are not!
"After this naturalistic description, to disentangle between potential ecological/game theory scenarios underpinning this behavior's expression, and measure features of collective behavior in multi-species groups, we're now running quantitative analyses on 'the gang'!"
The researchers argue that, for octopuses, the punching serves as a control mechanism for their partner fish when collaborative hunting, either to move them away from prey or to get rid of them from the group altogether.
They said: "To this end, the octopus performs a swift, explosive motion with one arm directed at a specific fish partner, which we refer to as punching."
The team - who looked at punches targeting several different fish species including tailspot, squirrelfish, blacktip, lyretail groupers and yellow-saddle - added: "These multiple observations involving different octopuses in different locations suggest that punching serves a concrete purpose in interspecific interactions."
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At times where fish are being opportunists and try to reap the advantages of the hunt without playing their part, an octopus might punch the fish out of competition.
But there were also other examples where an octopus punched a fish to retrieve prey.
"In these cases, two different theoretical scenarios are possible," the scientists added.
"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."
Featured Image Credit: Twitter/@OctoEduardo