Deciphering the octopus’ strange feeding habits
Octopuses can control which tentacles they prefer to specialize in catching certain types of prey, new research suggests.
Octopus prey attack moment.
Octopus prey attack moment.
Octopus prey attack moment. (Photo: University of Minnesota).
Using the California two-spot octopus, the researchers tested how the invertebrates responded when they placed crabs and shrimp in tanks. The octopus hides in the cave, leaving only one eye to look out.
Hundreds of fragments show that they constantly use the second middle tentacle, on the side of the viewing eye, to catch prey. They use other tentacles for support only when necessary.
While all eight tentacles share the same anatomy and are thought to be similar, using specific tentacles for specific movements reflects a particular evolutionary adaptation, the researchers said. .
Crabs and shrimps have different movement patterns and movement speeds, causing octopuses to use different attack styles. For example, the action of the second tentacle is like a cat jumping on a crab, because the crab’s crawl is much slower than the shrimp’s release.
Video: Please update your browser
Octopuses use their favorite tentacles to hunt
As for the more nimble shrimp, the octopus uses its second, but slower, tentacles to start its prey, then incorporates subtle movements to trick its prey.
The octopus, known for its ability to mimic during feeding, wiggles its tentacles near the shrimp to accommodate the movements of the shrimp’s tentacles and sensory hairs, reducing the likelihood of tail flicking. . After this tentacle catches the shrimp, the adjacent tentacles (1 and 3) come together to hold the shrimp in place.
It appears that the habit of attacking shrimp with its second tentacle has something to do with the octopus’ vision. The octopus only has very limited movement for each eye, but with 180 degrees of coverage and zero virtual intersection, combined with a non-moving head, the octopus most likely prefers to target in the middle rather than the edge. .
By simplifying the process of catching prey by using a second tentacle with the help of other tentacles when needed, an octopus can maximize its chances of foraging in the wild.
Here, biologists will analyze how neuronal activity is involved in these precise movements. They don’t think the octopus’ central nervous system is necessarily involved in controlling other tentacles to catch prey, but rather a reflex action.
According to them, a better understanding of the mechanisms behind the coordination of octopus tentacles will help in the development of soft robots, especially those that work underwater.
“If we understand the mechanics of octopus locomotion, we can apply it to create underwater vehicles or soft robotics applications,” said biologist and study author Professor Trevor Wardill of the University of Minnesota, USA.