Researchers find octopuses punch fish while hunting alongside them

LISBON, PORTUGAL—Ever get the urge to punch your hunting mate? Newly published research shows octopuses do. The research, published in Ecology on Dec. 18, has found while teaming up with fish to hunt, octopuses sometimes punch fish, occasionally for no apparent reason at all. Researchers even captured the behavior on video, which can be viewed at https://bit.ly/3ogodSy.

Typically solitary creatures, octopuses will sometimes take part in collaborative hunting with other fishes. In a December tweet, Eduardo Sampaio, one of the researchers involved in the study, said octopuses and fish hunt together to take advantage of each other’s physical attributes and specialized hunting skills.

Researchers from the Max Planck Institute of Animal Behavior and the University of Lisbon were studying these hunting parties when the punching behavior was discovered. Scientists documented eight distinct events in which the octopuses could be seen punching fish while conducting research in the Red Sea between 2018 and 2019 off the coasts of Israel and Egypt. The octopuses performed “a swift, explosive motion with one arm directed at a specific fish partner, which we refer to as punching,” the authors wrote. Victims included tailspot squirrelfish, black tip, yellow-saddle, and Red Sea goatfishes.

Although researchers have observed octopuses punching fish before, the behavior happening in the context of a hunting party is new.

In “this complex social network of interactions,” the authors wrote, “partner control mechanisms might emerge in order to prevent exploitation and ensure collaboration.” The authors speculate punches could be thrown by the octopus to maintain control over fish behavior, to banish certain fish from the group, to deter them from prey, or for purely selfish reasons—that is, to gain immediate access to a meal.

However, two of the eight events could not be immediately linked to a hunting episode or access to nearby prey. These punches occurred “in the absence of immediate benefits.”

“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,” Sampaio wrote on Twitter on Dec. 18.