Arctic belugas dive deep on one breath, powered by muscle oxygen
Beluga whales routinely descend to about 700 meters and stay submerged for 20–25 minutes on a single breath, thanks to lungs that collapse under pressure and gas exchange halting early so they run on an oxygen-rich muscle reservoir fortified by high myoglobin. This physiology, along with thick blubber insulation and heat-conserving circulation, lets them hunt deep beneath ice in near darkness. As Arctic ice retreats, changing habitat and increased predation add new pressures to these deep-diving specialists.