Why do seals swim with their belly and sea lions with their front fins? moving forward!
Very funny, smart, but where does this difference in the swimming style of animals that are so similar to each other come from? The difference was so remarkable that biologists had long suspected that seals and sea lions had different ancestors. But genetics disproved this: The species are so related genetically that they must have come from the same lineage.
Seals and sea lions are bainidites. Biology considers them to belong to the predator family, and they evolved from land-based predators that at some point moved their hunting grounds to coastal waters. This has resulted in such a variety of species (and swimming techniques) that walking into the water may not have been a one-time event, but rather many times; In different places and different conditions, with different results. But it is not known exactly how.
To help solve this evolutionary puzzle, researchers at Monash University in Australia took a closer look at swimming techniques for marine predators. And the biologists there were smart enough to bring in engineers skilled in aerodynamics. Through their joint research, which was just published in the trade journal Current biology, The footed swimming techniques appear to be less stringent than previously thought. There was no class of butterfly swimmers and a class of front crawlers there; All snails started out as foot swimmers, using their hind fins to move forward.
This remained the main driver of seals. Their front fins still showed where they came from; They look like claws, like a bear. And seals can still spread their fingers, too. Useful for carrying prey, but not great for performing swimming. The front fins seal is mainly used for cornering and braking, but they have very great resistance to generate high speed.
This varies with sea lions. Their front fins no longer look like a bear’s paw. They still have five fingers, but they are attached to a solid tissue and can barely move in relation to one another. The comb has become straight and there are greater differences in length, from the index finger, which is the longest, to the little finger. This results in front fins that resemble the wings of an airplane, with a distinctive teardrop-shaped cross section: thick at the front and thin at the back.
Grabbing prey is more difficult, but the front flippers become a more powerful swimming drive than the rear flippers. Researchers say that evolution in this branch of the shark family must be driven by an evolutionary advantage. They mainly think of fast prey, such as penguins and flocks of fish, that have become within reach of sea lions due to their high swimming speed. Under certain living conditions, this feature can be greater than the lack of claws.
Seals have been swimming with a transmitter off our coast for six months.
The animal was called Snow White, but it taught us a little, says Gilles Reomer.
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