Elephant Seal Map Sense Tells Them When to Return Home


Each year, pregnant female elephant seals trek for around 240 days over 10,000 kilometers across the eastern North Pacific Ocean before returning to their breeding beaches to give birth within five days of arrival. Now, a study published Feb. 28 in the journal Biology Current biology finds that this impressive navigation capability depends on an internal sense of the map, which works much like a built-in GPS.

“We found that migrating elephant seals know how far they are from their breeding range thousands of miles away,” said Roxanne Beltran of the University of California, Santa Cruz. “They also know approximately how long it will take them to get back.”

Beltran and his colleagues, including Dan Costa, knew that elephant seals are expert navigators. What they didn’t know was how the seals manage to get back to the beach just in time for breeding season.

In the new study, the researchers used satellite tracking data collected from more than 100 adult female seals. They understood when each of them turned around to return to the beach from which they had left.

The data revealed that the seals decided to turn back based on how close they were to where they needed to go. Their decisions to turn back were unrelated to their physical condition, measured in the amount of body fat.

“We were surprised that foraging success or body fat percentage was not more strongly related to when seals begin the return leg of the migration,” Beltran said. “We expected that the high performing (i.e. larger) seals would be able to complete their foraging journeys sooner, but this was not the case; instead, it appears that “They’re well-timed to strategically turn around based on where they are and how long it takes them to take them back.”

Researchers don’t yet know what sensory cues elephant seals rely on to know where they are and head in the right direction at the right time, but it’s clear they can adjust the timing of their movements based on an internal perception. of time and space.

The results help to better understand elephant seals, with important implications for their conservation, the researchers say. In future studies, they hope to quantify exactly how accurate the seals’ navigational ability is and determine which cues are most important.

The work was funded by the Office of Naval Research, the E&P Sound and Marine Life Joint Industry Project of the International Association of Oil and Gas Producers, and the National Science Foundation.

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