Researchers found that Physeter macrocephalus release bubbles while sleeping, helping the whale stay suspended about 80 feet below the surface. The study in the Journal of Experimental Biology reported that the behavior appeared during more than 90 percent of naps.
Journal of Experimental Biology
Researchers from Université de Neuchâtel and University of St Andrews studied 17 sperm whales off the northern coast of Norway over eight summers. They used Dtags to record blowhole sounds, depth and body position, then built a simulation using tissue density, drag coefficient and onboard gas volume.
The whales slept for seven minutes to more than three hours, and they rested in three ways: head-up, head-down before adjusting to head-up, and deep drifting. Whales near the surface blew more bubbles than those that began deeper in the water, pointing to a link between depth and the amount of gas they released. Miyoko Sakashita warns Gray Whales face 60 deaths on West Coast
Norway and buoyancy
The result fits the physics of a whale whose head can hold waxy oil equal to up to a third of its head space. That oil cools and becomes denser as the animal dives, then warms and expands as it surfaces, while lung air also expands on the way up. Even so, sperm whales are positively buoyant at the ocean surface and still manage to rest in a sleep-like state below it.
The study concluded that the whale reduces surface-borne gas volumes and actively regulates buoyancy during resting dives. That leaves a practical answer to the puzzle of how a large animal can remain below the waves while asleep: the bubbles are not an accident of rest, but part of the mechanism that keeps the body suspended. New Jersey Fireboat Whale Collision Sinks Carteret Marine Unit 2 Carteret Fire Department Boat sunk by whale strike in Raritan Bay
University of St Andrews
The study builds on earlier recordings of napping whales and pushes the question toward behavior across different depths and sleeping postures. It does not settle how the whales coordinate bubble release with each resting position, but it does show that the animals are managing buoyancy actively rather than drifting passively. That is the part to watch in future work from Université de Neuchâtel and University of St Andrews.
