The 1959 movie “Ben-Hur” runs some three-and-a-half hours long. A Cuvier’s beaked whale could watch the entire film underwater, never taking a gulp of air, with time to spare.
“They are remarkable divers,” said Nicola Quick, a marine biologist at Duke University. These pointy-snouted cetaceans, which frequent the world’s deep waters, have clocked the longest and deepest dives of any marine mammal ever recorded, plunging nearly 10,000 feet below the surface of the sea.
Dr. Quick’s latest paper, published Wednesday in the Journal of Experimental Biology, documents the whales’ most impressive observed descent to date: 3 hours 42 minutes, trouncing the previous record by over an hour. The new record is nearly seven times longer than scientists expect the mysterious mammals should be able to dive, based on scientific understanding of their body size and metabolic rate.
“This is just so beyond what we’ve seen before,” said Andreas Fahlman, a physiologist at the Oceanographic Foundation of the Valencian Community in Spain and an author on the study. “They’re not supposed to be able to do this, but they do.”
Most people, on the other hand, can’t hold their breath for more than a couple of minutes, although the Guinness Book of World Records documented one free diver who went more than 24 minutes without coming up for air.
The biology-bending stunts of beaked whales come with serious perks. By swooping down into light-starved layers of the ocean, the animals can find and feast on droves of fish and squid that are not accessible to most other predators.
But this predilection for the deep also places beaked whales among the least well understood mammals in the world, Dr. Quick said. Although they do occasionally ascend to breach, often it is only for a couple of minutes at a time, just enough to suck in a few breaths of fresh air. The whales are also boat-shy.
Still, with some nimble maneuvering, Dr. Quick and her colleagues were able to tag two dozen Cuvier’s beaked whales near Cape Hatteras in North Carolina. Between 2014 and 2018, the team tracked the whales’ movements as the animals undertook 3,680 foraging dives.
Previous calculations have estimated that Cuvier’s beaked whales, which can grow as large as 5,000 pounds and 20 feet long, should be able to store enough oxygen to sustain dives of 33 minutes. But the majority of the dives executed by the whales in Dr. Quick’s study lasted about an hour, with a small handful stretching past the two-hour mark.
Remarkably, the whales seemed unfazed by these feats: There was almost no relationship between the duration of their dives and the amount of time they spent recovering at the water’s surface.
“These guys blow right past the limit that’s seen with other species,” said Eric Angel Ramos, a marine biologist at the City University of New York who was not involved in the study.
One oddball whale managed two extreme dives, with one lasting 2 hours 53 minutes and the other for 3 hours 42 minutes. These numbers might be knocking up against the animals’ physiological limits, Dr. Quick said. But they are probably not typical, she added; both dives were recorded in the weeks after the whale had been exposed to a Navy sonar signal, a sound that is known to discombobulate and disturb marine animals.
At least a couple adaptations likely help the marine mammals survive and thrive during their deep dives, Dr. Fahlman said. For one, the whales are probably shunting blood flow away from their liver, kidneys and guts to free up oxygen for their brains, hearts and muscles — tissues essential for deep dives. At the same time, they might be lowering their heart rates to ramp down metabolism.
Lucía Martina Martín López, a marine mammal ecologist at the University of St. Andrews in Scotland who was not involved in the study, said that beaked whales might have an unusual muscle composition that makes their tissues less reliant on oxygen. Then, when oxygen stores eventually run low, the animals might have a way of tolerating the toxic chemicals that tend to accumulate in tired muscles.
Three-hour-plus-long dives might stretch the boundaries of human imagination. But to beaked whales, with their unique physiology, these deep-sea journeys may be just a walk in the park, Mr. Ramos said: “This shows how extreme mammalian physiology can get.”
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