Punching octopuses lead fish on hunting parties

Effective leaders consider all of their options before making a decision. They work with others from different backgrounds. They’re ready to give anyone who steps out of line a swift punch to the gills.

Scientists gathered these leadership lessons by watching a species commonly known as day octopuses, which roam the ocean floor in mixed-species hunting parties. A study published Monday in the journal Nature Ecology & Evolution suggests that while these undersea collaborations benefit both octopuses and their fish partners, the octopuses are in charge.

In earlier research, Eduardo Sampaio, an animal behaviorist at the Max Planck Institute of Animal Behavior in Germany, found that octopuses in mixed hunting groups would occasionally wind up one arm and wallop a fish. It wasn’t clear which fish were the most punch-worthy, or whether the fish and the octopuses were really working together. Fish might have been simply taking advantage of a cephalopod by following behind while it flushed out prey.

To explore those unknowns further, Sampaio and his colleagues captured video footage of 13 group hunts in the Red Sea. They then used computer modeling to reconstruct the hunts in three dimensions and analyzed which animals had influenced the trajectories of others in the group.

As a hunting pack traveled, the various types of fish fanned out around the octopus, Sampaio said, essentially providing options for where the group might go next. From these options, the octopus would choose a direction.

“The octopus was the one stopping them” from moving, Sampaio said.

When an octopus found an interesting crevice in the coral or rock, it would cover the crack with its body, trying to capture any prey inside. The octopus’s hunting was more efficient when it was traveling with fish partners: It checked out fewer crevices, but spent more time at each one, suggesting it was finding prey to slurp up. The most helpful partners were a species called blue goatfish.

Blue goatfish are team players even when there’s no octopus around, Sampaio explained. They like to work in pairs to corner their prey.

If an octopus sees blue goatfish or other hunting partners investigating a crevice, it gets the hint that something is hiding inside. It might grab the prey itself. Or the unlucky creature might make a dash out of the coral and into the mouth of a waiting fish. This is why fish, too, can benefit from teaming up.

Sampaio compared the octopus’s role in these groups to that of a chief executive, while the fish act more like a company’s research and development team.

“You can be a leader by pushing forward and expanding boundaries and taking the group to new places,” he said. “Or you can be the leader in terms of being the decider.” The octopus lets other animals study the marketplace and then chooses the company’s direction.

Marina Papadopoulou, a computational biologist at Swansea University in Wales who wasn’t involved in the research, praised the team’s gathering of quantitative data from their videos. Better understanding of collective animal movements in general can help in the conservation of other species, she said, as well as in the creation of algorithms for search-and-rescue drones.

However, Papadopoulou said, “I personally don’t like the use of the word ‘leadership’ when we talk about animals.” The word might make us imagine a boss making thoughtful decisions for everyone else, she said, but the movements of an animal group can emerge because everyone is following simple rules.

Papadopoulou said the octopus was more like an online influencer than a corporate executive.

While biologists usually describe octopuses as solitary, the cephalopods have shown in numerous ways that they pay close attention to the creatures around them, said Alexandra Schnell, a comparative psychologist affiliated with the University of Cambridge and a peer reviewer of the new paper.

In a hunting group, that attention to others means an octopus notices not only where its partners are searching, but also any fish not pulling its weight. Fish called blacktip groupers, Sampaio said, are exploiters. They follow the octopus and other fish without providing their own suggestions of where to go.

When the whole team stops moving and clumps around the cephalopod, Sampaio said, “then the octopus starts punching.” The exploiting groupers are the most likely to get whacked.

After all, Sampaio said, what do you do if some of the company’s workers are taking advantage of others’ work? “You start cutting their wages.”

This article originally appeared in The New York Times.

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