A unique technique. When it comes to hunting techniques, cetaceans are among the most creative animals: from the teamwork of the orcies to the technique of certain dolphins, which use the mud of the seabed to confuse prey. Among the most spectacular techniques, there is undoubtedly the known “bubble net“:
It belongs only and exclusively to the megatte and consists in exploiting air bubbles to surround and capture prey. To discover the reasons behind this so unique and singular strategy, a team of the University of Hawai conducted an in -depth study, published in the Journal of Experimental Biology:
Thanks to the use of drones and tracking devices, the researchers identified in the pectoral fins of the megattere the secret of their success.
Hunting with the bubbles. The bubble networks created by megattere work thus: large animals approach prey, usually numerous groups of fish or krill, and begin to swim in the circle, forming a kind of spiral. At each lap made, they approach the prey more and more.
During the composition of the spirals, the megattere emit from the vents of the air bubbles: these will come to create a real net that gradually tightens the prey, trapping them and allowing the cetaceans to swallow large quantities of food in a single bite.
Experts reflect on how in the end they are a technique that, in theory, could be used by any cetacean equipped with a vents. On the contrary, however, the “bubble net” has remained exclusive strategy of megattere. To find out why, the University of Hawai’i University team has traced the movements of a specific group of megattere, using drones for aerial filming and suction cup tags for geolocation.
In this way, the researchers were able to not only study the movements of the cetaceans during hunting with bubble nets, but also esteem their size and weight, to try to understand how they do animals so big to change direction so quickly to create their death spiral.
The secret is in the fins. The answer is in the pectoral fins: those of the megattere are the largest of the cetaceans, up to a third of their whole body. Alone they contribute to generating more than 50% of the strength necessary to perform their rapid changes of direction:
According to the authors of the study, if the other whales tried to do something like that they would need too much energy, definitely greater than what they would get from their meal.
Cameron Nemeth, the first author of the research, compares the mobility of the megattere “to that of a hunting pilot, such as those that are seen in Top gun“: a feature therefore makes them unique among the cetaceans.
