Sperm whales blow bubbles to sleep floating vertically
Researchers have discovered that sperm whales maintain a vertical sleeping position by releasing gas bubbles to regulate their buoyancy. This behavior helps them nap efficiently while avoiding the energy costs of deep-sea diving.
Why it matters
Understanding the unique biological and behavioral adaptations of marine mammals provides insight into ocean ecosystems and animal physiology.
They are the only whales that choose to sleep upright, but until now, scientists haven’t understood how it was possible due to their exceptionally buoyant heads.
Like humans, most whales sleep horizontally. Sperm whales however hang vertically in tight groups for short 10 to 15-minute naps.
It’s thought that this vertical sleeping enables them to sleep effectively by buffering them from surface wave action, while avoiding the expenditure of energy needed to dive to deeper depths.
The behaviour was first documented by naturalists in 2008, with the species being the only type of whale known to rest in a heads-up vertical position. But, researchers have long-been confused as to how these whales maintained their careful position, just below the sea surface.
New research from the University of St Andrews and Université de Neuchâtel has found that while resting, sperm whales release tiny gas bubbles to help them regulate their buoyancy.
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