Beluga Whales Dive 700 Meters for 25 Minutes as Lungs Shrink to 1/70 Volume

1 articles · Updated · spacedaily.com · Jul 22

700-meter beluga dives lasting up to 25 minutes are powered after descent by oxygen stored in myoglobin-rich muscles, not by active lung gas exchange.
At roughly 71 atmospheres of pressure, the whales’ lungs collapse in a controlled way, pushing air out of the alveoli into reinforced upper airways and sharply limiting nitrogen uptake.
Heart rates can fall from about 100 beats per minute at the surface to fewer than 20 at depth, while blood flow is redirected from skin and digestion to vital organs.
Blubber and counter-current heat exchangers help belugas conserve heat in near-freezing Arctic water, allowing repeated deep foraging dives for Arctic cod and Greenland halibut.
That adaptation suits life under sea ice, but retreating Arctic ice is exposing some beluga populations to more killer whales, fishing pressure and a changing winter habitat.