Sperm whales blow bubbles to stay afloat while resting, research shows

Sperm whales are the sole known species of whale that rest vertically, hovering just beneath the ocean's surface. Researchers have long theorized that these whales expel air bubbles to maintain buoyancy, but the specific mechanism behind this process remained unproven until recently. According to Noémie Freymond, a lead author of a new study from the Université de Neuchâtel in Switzerland, "We already knew that sperm whales rest in a stereotypical vertical position and that they had been observed releasing bubbles during these resting periods.

It had been hypothesized that the release of bubbles was related to buoyancy regulation, but this had not been demonstrated experimentally or systematically recorded."

Sperm whales possess a substantial oil-filled organ, known as the spermaceti organ, situated in their heads, which contributes to their buoyancy. This waxy oil is lighter than water, enabling the whales to remain afloat. The whales' lungs, respiratory tract, and spermaceti organ are all low-density organs located near the head, aiding in their vertical stability.

As the whales ascend, lower pressure causes air to expand in their lungs, propelling them towards the surface. To counter this upward force and prevent floating to the surface, the whales release bubbles. The study analyzed data from 42 sperm whales that had been tagged near Norway's Lofoten Islands.