Humans have sailed the oceans' surfaces for millennia, but their depths remain effectively uncharted. Only about a quarter of the seafloor has been mapped at high resolution. Maps of most regions display only approximate depths and often miss entire underwater mountains or canyons(峡谷).

So researchers have introduced some deep-diving experts: Elephant Seals. Scientists have been placing trackers on them around Antarctica for years, gathering data on ocean temperature. For a new study, the researchers compared these dives' location and depth data with some of the less detailed seafloor maps. They spotted places where the seals dove deeper than should have been possible according to the maps meaning the existing depth estimates were inaccurate.

In eastern Antarctica's Vincennes Bay, the diving seals helped the scientists find a large, hidden underwater canyon of more than a mile in depth. An Australian research ship called the RSV Nuyina later measured the canyon's exact depth using sonar (纳),and the researchers have proposed naming their find the Mirounga-Nuyina Canyon —honoring both the ship and the involved Elephant Seals, genus Mirounga.

But seals can't chart the entire ocean floor. The trackers used in the study could pinpoint a seal's geographical location only within about 1.5 miles, which allows for useful but not exactly high-resolution data. Plus, because the seals don't always dive to the bottom of the ocean, they can reveal only where the bottom is deeper than in existing maps- not shallower. Deep-sea research experts suggest improving on these data by using more precise GPS trackers and analyzing the seals' diving patterns to determine whether they have reached the seafloor or simply stopped going down.

The potential use of the current seal-dive data is to gather information about the deep ocean around Antarctica, specifically regarding the location and depth of sea-floor canyons. This data can be valuable for predicting how Antarctica's ice will melt. By understanding the presence and characteristics of these canyons, scientists can better assess how warmer water from the deep ocean flows towards the ice along the continent's coast, This knowledge is crucial for accurately modeling and predicting the future behavior of Antarctica's ice sheets and their contribution to sea-level rise.