The longest ever human free dive to date saw German freediver Tom Sietas take the plunge for 22 minutes and 22 seconds, an impossible feat for most. The record puts into perspective the impressive lung capacity of whales, the longest dive record of which has just been topped by a Cuvier’s beaked whale that spent a whopping 3 hours and 42 minutes underwater. The amazing feat, documented in the Journal of Experimental Biology, demonstrates the incredible adaptations that have enabled these gentle ocean giants to explore the big blue without needing to constantly dash to the surface for air.
The research saw 23 tags attached to Cuvier’s beaked whales for a 5-year stretch, recording more than 3,600 foraging dives. The results showed the average dive was around 59?min with just 5 percent of dives exceeding 77.7?minutes. The most spectacular recording of all however came in 2017 when one individual was recorded diving for an incredible 3 hours and 42 minutes, beating the previous mammalian dive record also set by a Cuvier's beaked whale of 2 hours, 17 minutes, and 30 seconds.
“We didn't believe it at first; these are mammals after all, and any mammal spending that long underwater just seemed incredible," said study author Nicola Quick in a statement. “It really did surprise us that these animals are able to go so far beyond what predictions suggest their diving limits should be.”
Exactly how such a feat is possible the researchers aren’t yet entirely sure but Quick suspects that the animals may have an exceptionally low metabolism. This combines with their above-average oxygen stores and tolerance of the sting that happens when lactic acid builds up in the muscles (if you’ve ever done a spin class you probably know the feeling), which occurs when the animals switch to anaerobic respiration at around the 33-minute mark, to make them some of the best divers in the world. Exactly what motivates such an epic descent isn’t immediately apparent but potential drivers could be a particularly fruitful food patch or a perceived threat or noise disturbance.
Interestingly, there appeared to be no set pattern for how long it took the whales to recover from their deep dives. One adult male resumed a foraging dive just 20 minutes after a 2-hour dive, while another spent the 4 hours after a 78-minute dive making shallow dives before making another deep foraging dive.
"Going into the study, we thought that we would see a pattern of increased recovery time after a long dive. The fact that we didn't opens up many other questions," said Quick.
Cuvier's beaked whales are elusive and little is really known about them as they spend most of their time underwater, surfacing infrequently. They are well known for being the ocean's diving champions though, also smashing the record for deepest dive, at 2,992 meters (about 1.8 miles).