Andy Coghlan in New Scientist:
The feat of wakefulness is remarkable given that rats die if forcibly denied sleep. And in humans, as any new parent will tell you, sleep deprivation is an exquisite form of torture.
The surprising sleeping patterns of captive killer whales – Orcinus orca – and bottlenose dolphins – Tursiops truncates – in the early months of life were observed by a team led by Jerome Siegel of the University of California at Los Angeles, US.
Unlike all animals previously studied, which maximise rest and sleep after birth to optimise healthy growth and development, the cetaceans actively avoided shut-eye. “The idea that sleep is essential for development of the brain and body is certainly challenged,” says Siegel.