When faced with a long trip home from a location they may not know well, sharks rely on their sense of smell to guide the way.
According to Live Science, the researchers tested a group of leopard sharks by taking them about six miles from shore and releasing them, only a certain amount had their sense of smell compromised by a Vaseline-soaked piece of cotton. Sure enough, the sharks without the cotton in their noses found their way back while the others showed signs of confusion.
"Although chemical cues apparently guide sharks through the ocean, other sensory cues likely also play a role. Future work must determine which environmental cues are most important for navigation and how they are detected and integrated," Andrew Nosal, a postdoctoral researcher at the Scripps Institution of Oceanography and the Birch Aquarium in California, said in a press release.
Nosal was the lead author of a study published in the journal PLOS One detailing the experiment. Like other sharks that live near the shore, the leopard shark has more developed olfactory bulbs other sharks do not.
"What was amazing is that sharks that could smell find found their way back to shore no problem," he told Discovery News. "We kidnapped them from their home, put them in a small holding tank, on the way out in the boat.
"We wanted to make sure the sharks couldn't retrace their steps. We covered the tank with opaque tarp so couldn't see sun, we aereated from a scuba tank, so there were no chemical cues. And we hung a strong magnet so no chance they could use geomagnetic cues. Yet upon release they could come straight back."
