To break the record for longest dive by a marine mammal, take a deep breath and jump in the water. Then don’t breathe in again for almost four hours.
Cuvier’s beaked whales (Ziphius cavirostris) are master divers (SN: 08/21/18). The creatures not only hold the record for deepest plunge by a marine mammal — measuring nearly 3,000 meters — but also for the longest dives. In 2014, scientists documented one dive that lasted just over two hours at 137.5 minutes, setting a record. Another Cuvier’s beaked whale has now shattered that record, going 222 minutes, or three hours and 42 minutes, without coming up for air, researchers report September 23 in the Journal of Experimental Biology.
To last so long underwater, the mammals may rely on large stores of oxygen and a slow metabolism. Once oxygen runs out, the animals may have the ability to tolerate lactic acid building up in their muscles from anaerobic respiration — a method of generating energy that doesn’t rely on oxygen. “These guys blow our expectations,” says Nicola Quick, an animal behaviorist at Duke University Marine Laboratory in Beaufort, N.C.
Calculations based on a seal’s oxygen stores and diving time limits hinted that the whales should last only about half an hour before running out of oxygen. Seals can exceed their limit about 5 percent of the time, so Quick’s team analyzed 3,680 dives by 23 whales. While most dives lasted around an hour, 5 percent exceeded about 78 minutes, suggesting it takes more than twice as long as thought for the whales to switch to anaerobic respiration.
The researchers expected to find that the whales spend more time at the surface recovering after long dives, but the team did not see a clear pattern. “We know very little about [the whales] at all,” Quick says, “which is interesting and frustrating at once.”