Sperm whales use bubble releases to stay submerged while resting

Scientists have discovered that sperm whales resting just below the ocean surface release bubbles to counteract their natural buoyancy and remain submerged. The whales adopt a vertical posture with heads pointing upward, a position that protects them from surface waves while allowing quick access to air.

Researchers attached suction‑cup tags to whales off the coast of Norway, recording sound and three‑dimensional movement. The data showed that during short resting bouts of about 10–15 minutes, whales emitted bubbles roughly 11 times, significantly more than during ascent from deep dives. The bubble releases reduce the positive buoyancy caused by the large amounts of spermaceti oil in their heads, preventing the animals from unintentionally floating to the surface.

The study was led by Professor Patrick Miller of the University of St Andrews, with collaborators from the University of Neuchâtel in Switzerland. The findings highlight how advanced tagging technology can reveal previously hidden underwater behaviors and improve understanding of the conditions needed for these deep‑diving mammals to rest safely.