Sharks Use Seamounts as Compass to Navigate Undersea


National Geographic Sea Bird, Gulf of California — The National Geographic Committee for Research and Exploration (CRE) got to travel into the ocean realm of one of its most celebrated shark researchers last week when it it was accompanied on a field inspection in the Gulf of California by Pete Klimley.

The recipient of 11 National Geographic grants, Klimley is known on the National Geographic Channel, PBS and YouTube as “Doctor Hammerhead” for his work with the scalloped hammerhead shark (Sphyrna lewini).

“We’ve come back to a place to where I started studying hammerheads in the late 1970s,” Klimley told me as we stood on the deck of National Geographic Sea Bird watching the sun rise over the calm waters of the Sea of Cortez. “I have a predilection for this place, because it is where I started. I went out to a seamount here and in what was an area the size of a small auditorium I found a huge number of hammerhead sharks, at least 500.”

Intrigued by so many sharks in one small place, Klimley wondered what they were up to. “I quickly found out that they were primarily female and that they were fighting amongst each other, and that males were then pairing with the dominant females. So that’s why they formed such big schools,” he said.

“They were swimming like we would drive a car down a highway.”

But why do all this at that seamount? “My later studies focused on that. That’s when I found that sharks could go ten miles or more out to sea in the middle of the night, and then come back without any difficulty. I fashioned a little compass sensor to record how straight they were traveling; they were swimming like we would drive a car down a highway, directly from one —> Read More