Natures wonders: shark magnetic field migration (Introduction)

by David Turell , Friday, May 07, 2021, 14:43 (1294 days ago) @ David Turell

Another creature joins the magnetic field group:

https://www.sciencemag.org/news/2021/05/sharks-use-earth-s-magnetic-field-navigate-seas...

'A new study suggests some sharks can read Earth’s field like a map and use it to navigate the open seas. The result adds sharks to the long list of animals—including birds, sea turtles, and lobsters—that navigate with a mysterious magnetic sense.

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"Bryan Keller, an ecologist at Florida State University, and his colleagues decided to do just that. The researchers lined a bedroom-size cage with copper wire and placed a small swimming pool in the center of the cage. By running an electrical current through the wiring, they could generate a custom magnetic field in the center of the pool. The team then collected 20 juvenile bonnethead sharks—a species known to migrate hundreds of kilometers—from a shoal off the Florida coast. They placed the sharks into the pool, one at a time, and let them swim freely under three different magnetic fields, applied in random succession. One field mimicked Earth’s natural field at the spot where the sharks were collected, whereas the others mimicked the fields at locations 600 kilometers north and 600 kilometers south of their homes.

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"When the applied field was the same as at the collection site, the researchers found that the animals swam in random directions. But when subjected to the southern magnetic field, the sharks persistently changed their headings to swim north into the pool’s wall, toward home, the researchers report today in Current Biology (see video, below). “[This] suggests they’re able to use magnetic fields for long-distance migration,” says Neil Hammerschlag, a shark ecologist at the University of Miami who was not involved in the study.

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"With magnetic navigation now demonstrated in so many animals, Winklhofer wants researchers to figure out the underlying mechanism. Some say the sense relies on cells containing a magnetic iron mineral, magnetite, whereas others invoke a protein in the retina called cryptochrome. “All the other major senses have been described and understood,” Winklhofer says. “The key question is how do they do it?'”

Comment: The underling mechanism probably uses magnetite as in other species. Evolution as designed by God uses the same process over and over.