Octopuses, known for their solitary nature, have been discovered by researchers to exhibit complex cooperative hunting behaviors with fish, demonstrating leadership skills and collective action.
A new study published on September 23 in the journal Nature Ecology & Evolution details how octopuses and various fish species collaborate to successfully hunt for mollusks and crustaceans in groups. Each species assumes specialized roles to maximize overall success.
Day octopus hunting cooperatively with black-striped fish and yellow-striped fish. (Photo: Eduardo Sampaio & Simon Gingins)
Eduardo Sampaio and his team conducted multiple exploratory dives in the Red Sea, monitoring and observing 13 hunting groups, including one day octopus (Octopus cyanea) along with several fish species such as surgeonfish, grouper, and snapper. “We were amazed at how sophisticated these hunting groups could be,” Sampaio shared.
The day octopus is commonly found in tropical coral reefs from Hawaii to East Africa and can grow nearly one meter long, according to the Monterey Bay Aquarium. Their name comes from their daytime hunting behavior, which is unusual as most octopus species hunt at night. When capturing prey like crabs and clams, the octopus kills its prey with venom secreted from its salivary glands, then breaks open the shell with its sharp beak. Day octopuses learn very quickly, but they have a short lifespan of about one year and reproduce only once in their lifetime.
By tracking the three-dimensional movements of hunting groups over 120 hours of video footage, researchers found that the dynamics within the groups were much more complex than previously thought. They had assumed that octopuses directed the hunt, but the study revealed that leadership is shared among the species, with different animals contributing their unique skills to the group.
The fish, particularly the surgeonfish, are responsible for exploring the environment. Based on their sensory capabilities, they decide where the group should go. Meanwhile, the octopus determines whether the group should proceed to the next step and when to do so, using its intelligence and agility to benefit from the fish’s discoveries. According to the research team, this shared decision-making reflects a new understanding of leadership roles in multilateral groups, where both promoting and inhibiting movement can shape group behavior.
The research team observed how group composition affects the behavior of each species. For example, some fish species will put more effort into leading the group when cooperating with an octopus. This collaboration also triggers a “partner control mechanism,” where the octopus sometimes punches the fish to position them or assert dominance. Despite these aggressive moments, the group operates effectively, increasing their chances of successful hunting compared to when the octopus or the fish hunt alone.
Another important detail about the octopus’s rough punches is that they are one-sided, meaning that fish never attempt to push their partners out of the group since they need the octopus to drive prey out of hiding places.
This newly discovered behavior challenges the traditional view of octopuses as solitary and non-social creatures. The study demonstrates that octopuses can collaborate with other species, showing signs of social competence and cognitive flexibility. Octopuses adjust their actions based on the behaviors of their fish partners, exhibiting a level of social intelligence previously unseen in this species.
