Science briefs: Why do humans have eyebrows?

Sea turtles use the Earth's magnetic fields to navigate back to the area where they were born decades earlier, said a study that used loggerhead genetics to investigate their travels. After swimming for years in a giant loop from nesting grounds in North Carolina and Florida to North Africa, the turtles find their way back to nest on beaches within about 40 to 50 miles of where they were born. The study suggests that the turtles learned their home beach's distinctive magnetic signature, through what is called geomagnetic imprinting.

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