LONDON, Sept 24 — A rare video has captured octopuses hunting alongside fish, revealing an unexpected level of cooperation between the species.
The footage, part of a study published in Nature yesterday, shows the social interactions of the octopus species Octopus cyanea, also known as the big blue or day octopus, as it hunts in groups with several species of fish.
NBC News reported that the findings offer new insights into octopus behaviour, challenging the previous belief that these animals hunt alone.
“I think sociality, or at least attention to social information, is way more deep-rooted in the evolutionary tree than we might think,” said Max Planck Institute of Animal Behaviour postdoctoral researcher and the study’s lead author Eduardo Sampaio
“We are very similar to these animals. In terms of sentience, they are at a very close level or closer than we think toward us,” he added.
The study found that some octopuses display complex social behaviours, suggesting that at least one species has traits and markers of intelligence once thought to be exclusive to vertebrates.
Researchers also observed that the octopuses punched fish during hunts to maintain order.
“The ones that get more punched are the main exploiters of the group,” explained Sampaio.
He described these fish, including blacktip groupers, as ambush predators that remain stationary, relying on the octopus to find prey.
Sampaio noted that octopuses benefit from hunting with fish because they can follow the fish to their prey instead of searching on their own.
“If the group is very still and everyone is around the octopus, it starts punching,” he said.
“But if the group is moving along the habitat, this means that they’re looking for prey, so the octopus is happy.”
The study, which involved 120 hours of footage collected over a month off the coast of Eilat, Israel, tracked 13 octopuses during 13 separate hunts.
Using 3D modelling, the researchers mapped the movements of both octopuses and fish to study their interactions.
One fish species, the blue goatfish, appeared to play a key role in guiding the hunting group.
“They are the ones exploring the environment and finding prey,” Sampaio said.
He noted that while the goatfish led the group, the octopus ultimately acted as “the decider.”
Despite this cooperation, there was no evidence of prey-sharing. Each species ate what it caught.
The research raises questions about whether octopuses recognise specific fish companions or prefer to hunt with certain individuals.
Sampaio wondered, “Do I want to follow the blue goatfish or do I want to follow Martha because I’ve hunted with Martha before?”
London School of Economics professor of philosophy Jonathan praised the detailed analysis of the octopus hunting behaviour.
“It’s an important step beyond what you get in nature documentaries,” he said.
He commended the study for observing the animals in their natural environment rather than a laboratory setting.
“They just seem to be so much more expressive in the wild and be capable of so much more,” Birch added.
For years, octopuses were seen as a challenge for evolutionary theories of intelligence because they were believed to be intelligent but solitary.
Birch explained that this study shifts the thinking towards a more socially complex view of octopus behaviour.
“For at least one species of octopus, there is quite a rich social life of a kind,” he said.
