Sperm Whales Use Bubbles to Stay Afloat While Resting, Study Finds

Scientists have long observed sperm whales resting vertically in the ocean, but the mechanism behind their ability to stay neutrally buoyant was unclear. A new study has demonstrated that the whales release air bubbles to counteract the upward push of their low-density organs, allowing them to stay submerged. The research team, led by Noémie Freymond, used data from 42 sperm whales tagged with suction cups near Norway's Lofoten Islands. The whales' massive oil-filled spermaceti organ, located in their heads, makes them buoyant due to the lighter-than-water waxy spermaceti oil. As the whales drift up, lower pressure allows air in their lungs to expand, pushing them toward the surface. Releasing bubbles counteracts this effect, enabling the whales to rest steadily just below the ocean's surface. This study provides the first experimental evidence of the whales' bubble-releasing mechanism, shedding light on their unique behavior.