This is Scientific Americans 60 Second Science.

I'm Jason Goldman.

Got a minute?

Some sea creatures can find their way through thousands of miles of seemingly featureless oceans.

Even more impressive is the route that they take.

Well, we've known for a long time that sharks are capable of long distance migrations.

And in some cases, those migrations occur along very straight paths.

Scripps Institution of Oceanography biologist Andy Noesalle.

And this has always begged the question how exactly do they know where they're going?

So there have been a lot of hypotheses floated over the last several decades, including the ideas that

D sharks are using, for example, geomagnetic cues,

chemical cues, and others.

But none of these have really been systematically

tested in the field.

No cell in his team suspected that the navigational secret of some sharks might be their sense of smell.

They use their keen noses to find food, of course, and other fish like salmon are known to

use olfaction to navigate.

To see if his hunch was right, No Sal scooped up some adult female leopard sharks in their preferred

environment, waste deep water off the San Diego coast.

He attached a small radio transmitter behind their dorsal fins, and he blocked the sense of smell in half of the sharks by shoving cotton balls soaked with petroleum jelly into their nostrils.

No cell and his crew dropped the sharks about six miles away at a spot in the open ocean.

The researchers then tracked the sharks as they tried to swim back home.

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