An octopus hunting with yellow-saddle mullet and blacktip grouper
Photo: Edward Sampaio/Simon Gingins
A bizarre-looking “Day Octopus,” not exactly worthy of a beauty prize, swims astonishingly elegantly through the clear waters of the Red Sea. In the English-speaking world, the Octopus Cyanea, with its sac-shaped body with eight tentacles equipped with suction cups, is so called because it is the only octopus species that hunts for prey during the day. That’s lucky for Eduardo Sampaio and his cameraman. In the light-flooded water they manage to capture wonderful videos of the Great Blue Octopus, as Day Octopus is called in German, surrounded by colorful fish.
Octopods fascinate researchers and laypeople alike. Octopuses are shy, solitary creatures, but when it comes to eating, the Great Blue Octopus overcomes this trait and uses its intelligence, curiosity and ability to learn. In search of crabs, mussels and crabs, he teams up with fish to hunt. These usually consist of an octopus and up to 13 different species of fish such as the yellow-saddle mullet or the blacktip grouper.
It is precisely this behavior that has fascinated the Portuguese Sampaio for many years. In his paper published this week in the journal “Ecology”. Study The scientist from the Max Planck Institute for Animal Behavior at the University of Konstanz refutes the previous assumption that the octopus, native to the Pacific and Indian Oceans, leads the hunting party and the fish follow it.
After more than 120 hours of diving with video cameras, Sampaio and colleagues were able to show that the interaction between octopuses and fish is very complex and dependent on the situation and purpose. The yellow-saddled mullet specializes in exploring the surrounding area and thus gives the hunting group the direction, according to the study, while the octopus decides when and where exactly to strike. »The octopus adapts its behavior to the behavior of other species, waits for the fish to explore the environment and then moves directly to where the prey is. Fish communication can be passive (based only on movement towards the prey) or active (coming and going movements between the octopus and the prey location),” explains Sampaio in an email to “nd.Die Woche”. The point of the exercise is obvious. “When he is alone, he has to explore the environment himself, which is much more time-consuming,” says the octopus expert. In modern German, this is a classic win-win situation.
It is not unusual for different species to cooperate for different reasons. Animal species such as gazelle, wildebeest and zebra form a defensive network against predators. For others, hunting is the main focus. Badgers and coyotes, for example, often hunt small mammals together. Moray eels and groupers also work together to get food. “However, these appear to be less flexible in their behavior than the hunting group made up of octopus and fish when it comes to exchanging information about changing strategy,” says the study.
True to the motto “First comes food, then morals” there is no unconditional cooperation when octopus and fish hunt together prey. Fish aggressively chase other fish away or the octopus pushes fish away with brute force. »This means that the groups are neither exclusively cooperative nor competitive. Your character develops gradually and depends on the composition of the group. That is, when there are more exploiters, there are more aggressive control mechanisms, when there are more collaborators, there is much less or no aggression,” explains Sampaio.
Sampaio is fascinated by the Great Blue Octopus. It is astonishing, says Sampaio, how an animal that split off from vertebrates 550 million years ago could develop such complex behavior. “It is also amazing how a non-social species like the octopus can learn social rules and maximize interaction with individuals of other species.”
»The octopus adapts its behavior to the behavior of other species.«
Eduardo Sampaiobehavioral biologist
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