Marine mammals such as seals and whales require highly equipped bodies to dive beneath the waves, withstand the intense stress of the deep ocean, and go without oxygen for a prolonged duration.

This is because mammals like fish only obtain oxygen by breathing air near the ocean’s surface.

“For anything that breathes air and then forages at depth, you’ve got this real disparity that most animals don’t have to deal with,” Nicola Quick, a marine researcher at Duke University in North Carolina, said to Live Science. “One of their critical resources, air, is in one place — and their other critical resource, which is food, is in another place.”

Which mammal can be said to dive most profoundly?

This title could be attributed to Cuvier’s whales with beaked heads ( Ziphius cavirostris), which are mid-sized whales found in tropical and temperate oceans worldwide. Researchers began attaching GPS trackers to the whales near California waters to monitor their movements. Then, they observed the whales’ remarkable diving skills.

A whale could tag dived into the water at 9,816 feet (2,992 meters), approximately 32 times the size of the Statue of Liberty. Furthermore, the whales could dive for an extended period if they stayed in the water for over two hours.

In 2020, Quick and her colleagues saw a record-breaking dive when they saw the Cuvier’s beaked whale stay submerged for three hours and 42 minutes. This dive was not included in the official findings of their research because it was following exposure to sonar which may have affected the whale’s behavior. However, the study pointed out that a dive of this length could signify “the true limits of the diving behavior of this species.”

The author of the research paper pointed out three aspects that allow whales to achieve such deep dives. The first is that the blood of whales contains high levels of hemoglobin and myoglobin proteins, allowing them to store plenty of oxygen. Whales also limit the amount of blood pumped into the body’s outer areas to ensure that vital organs are getting sufficient oxygen.

The whales may require a way to eliminate the lactic acid they produce when swimming — however, Quick stated that it’s not clear how they can do this.

Deep-diving mammals have to be able to endure the pressure that comes with diving thousands of feet underwater. The most challenging thing to keep open under high-pressure conditions is the lungs, which contain pockets of air that could collapse under extreme pressure. However, diving mammals can use the capability to flatten lung chambers when descending to decrease the amount of airspace they must keep open in the face of pressure.

Quick stated that scientists believe Cuvier’s beaked whales have been scouring to find food as they dive. However, they don’t know the food they’re consuming in the depths — although one study from 2017 suggests it’s mostly Squid.

Other marine mammals are also able to be found diving beneath the surface. Southern Elephant seals (Mirounga leonine), For instance, have been seen descending to as deep as 6,560 feet (2,000 meters) deep, like Sperm whales (Physeter macrocephalus).