Scientists caught small hammerhead sharks and placed them in a pond surrounded by copper wires. Researchers can use this to simulate magnetic signals. They reproduced the signals from the site where the animals were captured, in Saint George Sound, and from sites 375 miles (600 km) north and south of that location.
When the signals came from the south, the animals began to swim north. This indicates that they want to return to the home where they were captured. When the magnetic signals simulate their home, the sharks swim in different directions. When the signals came from the north, the animals looked confused because they hadn’t reached there. With this in mind, scientists have concluded that sharks can distinguish geographical locations with the help of the geomagnetic field.
“We knew a while ago that they have the ability to detect the magnetic field, but this is the first time they have been successfully tested using those skills to infer their position,” said study author Brian Keeler.
Keeler and his team believe other sharks must have some sort of built-in GPS system. It just doesn’t make sense to them that only hammerhead sharks have evolved such a thing and that other sharks that also travel long distances don’t.
From South Africa to Australia and back
According to Science Magazine, in 2005 a white shark was tracked swimming from South Africa to Australia and back, roughly in a straight line. Scientists, for example, began to believe that sharks were using Earth’s magnetic forces to guide, as has been observed in seabirds, lobsters, and sea turtles.
However, very little research has been done on this topic to date. The study was the first step toward proving that sharks have an internal navigation system, but more research needs to be done, according to other scientists.
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