Marine researchers in Japan and elsewhere have discovered yet another conundrum of the water world. In a new newspaper that comes out Thursday, they describe their finding different types of large sea creatures, from turtles to sharks to seals, swim in circles for no apparent reason. This circling could have different purposes for the animals, such as to aid in their navigation or search for food, the researchers say.
According to the researchers, recent advances in technology have allowed scientists to get a more complete picture of how animals in the ocean move through them environment with much better precision than before. Lead author Tomoko Narazaki, from the University of Tokyo, and colleagues decided to put this technology to good use by observing the movements of green sea turtles during their breeding season, when female turtles return to their hometown to lay eggs.
They moved turtles from their nesting location to elsewhere so they could observe how they navigated back to their original site. But once they did, they saw a peculiar pattern: The turtles often circled at least twice at a relatively steady speed and then returned to normal swimming. as they ventured back House.
Curious, Narazaki told others in his field about the discovery. He ended up working with some of these researchers to look back at movement data that had been previously collected a range of other sea creatures across different branches of the evolutionary tree. Sure enough, they found the same kind of circular behavior popping up repeatedly. These circling animals include fish (tiger sharks), birds (king penguins), and mammals (Antarctic fur seals and Cuvier beaked whales).
Their work is published in iScience.
“All data used in our research was initially collected for different purposes (eg.g., to study the foraging behavior of sharks etc.). Data from each species was analyzed for different aspects by different co-authors, ”Narazaki told Gizmodo in an email. So it took awhile before we realize that this circling is a common behavior among many species – until we worked together. “
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Circling the surface is hardly practical for the survival of these animals, as the most energy-efficient way to travel anywhere in the ocean is usually a straight line. So that probably means it has one or more important features that are worth the extra effort. But right now, all the team has is some knowledgeable guesses about what’s going on, which can vary between different types.
For example, the sharks most often seem to circle around where they get food, indicating that it offers some benefit in huntingMeanwhile, other research has shown that some species of whales will use circling in groups as a way to create “bubble nets” to catch their small fish. But feeding probably isn’t the only goal for getting around.
In at least one male tiger shark, the team found evidence that circling was part of that courtship ritual for a woman. Seals and penguins most often appear to circle the surface of the water or outside their typical forumswent for hours, both of which indicate that it is not part of their feeding technique. The team also cited previous research that found northern elephant seals circling during their drift dives – lazy, passive dives that help them rest or process their last meal.
In the turtles, circling can help them refocus their dependent navigation skills on smell, sight and to feel magnetic fields. The turtles often circled just before the last leg of their journey, and for a while, to. A turtle was observed to circle a whopping 76 times before continuing.
“Given that similar circular behavior has been observed in a wide variety of marine megafauna taxa, it is possible that it is a behavioral convergence with similar purposes,” said Narazaki. “But for now, the purpose and function of this behavior remains unknown.”
Of course we know that there are many animals circling the land for various reasons (ask your nearest dog before he poops). But the ambiguity of the vast ocean means there are probably all kinds of behaviors among these animals that we simply haven’t seen yet. By studying the how and why of the navy Circling closer, the researchers hope to shed more light on this almost strange world.
“For the next step, we want to investigate the movements of animals in relation to the internal state of animals and the environmental conditions to investigate why they circle,” said Narazaki. “Some hypothesesexperiment testing would be necessary to understand the function and mechanism of circular motions. “