Seals dozing on the beach may appear to be enjoying the ultimate life of leisure. However, groundbreaking research has revealed that for most of their lives elephant seals sleep just two hours daily in a series of short naps while performing deep dives.
The findings, revealed in the first study to record brain activity in a free-ranging, wild marine mammal, show that during the months they spend at sea, elephant seals rival the record for the least sleep among all mammals, currently held by African elephants. The seals were found to typically sleep in 10-minute bursts during deep, 30-minute dives, often spiralling downwards while dreaming, and occasionally lying down for a nap on the seafloor.
