Eight octopus arms against a set of fish fins might sound like a rigged match. But when it comes to settling territorial conflicts, all means appear to be fair, and the octopus’s behaviour shows it does not simply flail around. Instead, it adapts to the particular fish it encounters.
Not every fish ends up in the octopus’s crosshairs. A study published in the journal Behavioural Processes found that only certain fish were targeted. Researchers followed 38 young octopuses off the coast of Brazil and filmed 101 encounters, some with territorial fish and some with non-territorial ones.
When an intruding fish appeared, the interaction lasted an average of 14 seconds. The fish made jabs and quick lunges, and the octopus responded with arm strikes. Fish that behaved more amicably were allowed to follow and swim close, in exchanges that lasted an average of 46 seconds, evidence, the researchers said, that the animals adjust their conduct depending on the type of fish in front of them.
A striking example is a previously undocumented colour pattern in which the octopuses develop distinct white spots on the side of their skin facing the intruding fish. The team noticed that the fish tended to back away as the skin changed, suggesting the display works as a deterrent.
The researchers also found that individual octopuses have different personalities, some shy and others more reactive, though they shared one trait: curiosity about the humans studying them. The octopuses repeatedly tried to touch the cameras, and one managed to steal a diving weight and carry it back to its nest.
