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What can a seal teach us about the deep ocean? Plenty-as long as it’s wearing satellite-linked devices on its head. Clive McMahon, who works on an elephant seal tagging project at the University of Tasmania in Australia, said that deep-diving seals can provide scientists with a wealth of information on the structure of the ocean floor.

To gather this information, McMahon and his team attached small satellite-linked devices to seals. The devices took measurements of temperature and depth as the seals swam. Since 2004, McMahon’s team has tracked more than 500, 000 individual seal dives beneath the East Antarctic continental shelf, which is the edge of a continent that lies under the ocean.

“Given the remote nature of Antarctica and the surrounding Southern Ocean, only a small part of the Antarctic continental shelf was surveyed by ships in the past,” McMahon said. “So the information available about this area is sparse.” But seals are helping scientists fill in the pieces to this puzzle. In July 2023, McMahon and his team published a study about their work with deep-diving seals in a scientific journal.

Information from seal dives is helping scientists understand how the ocean affects Antarctica’s role in global climate. “We found in some regions that more than 25 percent of previous estimates of the ocean depths were wrong.” said Mark Hindell, who also worked on the study. “We only know this now because the seals were diving hundreds of meters below those depths. In the most extreme cases, they dived more than 1, 000 meters (3,281feet) deeper than what we thought was the ‘ocean floor’”.

The data, or information, from the dives also revealed new underwater features, including troughs, which are long, wide and deep sunken areas in the ocean floor. Thanks to the seals, the scientists also found a deep canyon near the Vanderford Glacier, which is as low-moving river of ice hundreds or thousands of meters deep.