Octopuses cooperate with fish to hunt, but the way they share decisions is surprisingly complex

A new study published in Nature Ecology & Evolution sheds light on what happens when octopuses and fish hunt together. As it turns out, this cross-species relationship is more complicated than anyone expected.

Animals of the same species often cooperate and work together to achieve some goal. However, cooperation between individuals of different species is relatively rare.

A classic example you may be familiar with is the close relationship between dogs and humans in sheep herding and hunting situations. In these situations, dogs and humans work together to achieve a goal.

That’s a mammal. But aquatic species may also cooperate. A good example is the joint hunting behavior of moray eels and groupers. The grouper approaches the moray eel and signals that it wants to hunt. The eel responded in kind and departed.

During these hunts, groupers use signals to indicate where prey is hiding in the coral matrix. This is truly a heavenly synergy. Eels can threaten prey from hiding spots among corals, while groupers patrol above them. There is literally nowhere for prey to hide.

Eels and groupers have a much better chance of catching dinner when they hunt together rather than alone.

Who is in charge here?

Researchers have described this behavior before, but one question remains unanswered. Who is in charge of these cross-species interactions?

Who decides what to do, when and where? Are the various players “democratic” in that they somehow compromise, or are one species taking the lead while the other Do species simply obey (i.e., are they “tyrannical”)?

Biologist Eduardo Sampaio and his colleagues investigated cross-species interactions between the normally solitary Japanese octopus (Octopus cyanea) and several fish species, including goatfish and grouper.

Fish and octopus have a common goal of increasing hunting efficiency. The traditional view of octopus and fish hunting groups assumed that the octopus was the producer, and that the fish simply followed and picked up the detritus at any opportunity.

The octopus uses its long, flexible arms to explore every nook and cranny of the hunting ground, scouring the prey available for fish. In this scenario, the octopus is solely in charge of decisions and the fish simply follows suit (i.e., an exploitative and tyrannical relationship).

But when researchers looked closer, they found that the relationship was probably not as simple as previously believed. However, without detailed analysis that provides hard evidence, it is difficult to elucidate exactly how this cooperation works.

What did the new study find?

Using advanced behavioral analysis of 3D videos taken during 120 hours of diving, Sampaio and his team found that each partner played a specific role in the interaction. In fact, there were no true leaders. they are democratic.

The fish is responsible for exploring the environment and deciding where to move, and the octopus decides if and when to move. Interestingly, control experiments showed that the octopus was guided by social information provided by the fish.

When combined with green goats, the octopus’ foraging tactics become more focused and efficient. Not so much when partnered with the Tsumahata. The nature of hunting relationships therefore varied depending on who was involved.

The researchers concluded that, overall, octopuses that forage with partners, such as fish, have a higher success rate in catching prey.

The details uncovered in this study suggest that this relationship is much more sophisticated than other interspecific hunting associations examined to date.

Despite the large evolutionary gap between these animals (equivalent to about 550 million years), both fish and octopuses show clear signs of social abilities and advanced cognition.

This article is republished from The Conversation under a Creative Commons license. Read the original article.