Marine researchers in Japan and elsewhere have discovered another enigma of the water world. In a new paper released Thursday, they detail their findings various species of large cetaceans, from turtles to sharks to seals, swimming in circles for no apparent reason. This rotation could have a number of causes for the animals, such as supporting their navigation or foraging, the researchers say.
According to the researchers, recent advances in technology have allowed scientists to gain a more complete picture of how animals in the ocean pass through. environment with much better precision than before. Lead author Tomoko Narazaki, of the University of Tokyo, and colleagues they decided to put this technology to good use by watching the movements of green sea turtles during their nesting season, when female turtles return to their place of birth to lay eggs.
They moved turtles from their nesting site to other areas, to see how they moved back to their original location. But once they did, they saw a distinct pattern: the turtles would often roam at a relatively constant speed at least twice around, and then return to their normal swimming. as they return home.
Strangely enough, Narazaki told others in his field about the discovery. Eventually, he joined some of these researchers to look back at movement data collected earlier. a range of other marine animals across different branches of the evolutionary tree. And sure enough, they found the same kind of circulatory behavior again. These circulating animals included fish (tiger sharks), birds (king penguins), and mammals (Antarctic and C fur sealsuvier forked whales).
They have their work published in iScience.
“All the data used in our study was initially collected for a variety of purposes (e.g., to investigate shark hunting behavior etc.). Data of each species were analyzed by different co-authors for different aspects, ”Narazaki told Gizmodo in an email. “So he took it long before we realized that this circulation is a common behavior across many species – until we collaborated. “
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On the surface, circulating it is almost impractical for these animals to survive, as a straight line is usually the most energy efficient way to travel anywhere in the ocean. So that probably means he has one or more tasks worth the extra effort. Currently, however, the entire team is getting a measure of what’s going on, which may vary between different species.
The sharks, for example, seem to usually roam around where they find food, showing that it gives some advantage in hunting. Meanwhile, there is other research on it shown that some species of whales use group rotation as a means of creating “bubble nets” to catch their small fish prey. But feeding is not the only reason for circulation.
In at least one male tiger shark, the team found evidence that circulation was part of it courtship ritual in front of a woman. Seals and penguins appear to roam mostly near the surface of the water or outside their usual forums.sometimes ging, which both indicate that it is not part of their diet. The team also built on earlier research to find that northern elephant seals roam when diving – lazy, tolerant divers who help them relax or process their last meal.
In the turtles, rotating may help them to redirect their sailing skills, which are on smell, sight, and awareness magnetic fields. The turtles would often roam just before the last part of their journey, and for a while, also. One turtle was observed circling a whopping 76 hours before moving on.
“Given that similar circulatory behavior has been observed across many types of marine megafauna support, it may be possible that it is a behavioral convergence with similar causes,” Narazaki said. “However, for now, the purpose and operation of this behavior is not yet known. ”
In fact, we know that there are many animals on an earth circle for various reasons (just ask the nearest dog mus poops e). But the clarity of the ocean means that all forms of behavior are common among these animals that we have not just seen. still. By examining how and why the sea exists circulating closer, the researchers hope to illuminate this almost alien world a little more.
“For the next step, we would like to study the movements of animals in terms of the state of the environment and the environment of animals to examine why they are circulating,” Narazaki said. “Opinion-pilot tests would be required to understand the function and equipment that underlie circulatory movements. ”