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Newborn dolphins, killer whales never sleep -study

Posted on: Wednesday, 29 June 2005, 18:47 CDT

LONDON (Reuters) - Sleep-deprived mothers of newborn babiesshould spare a thought for bottlenose dolphins and killerwhales.

A study has shown the young of those two species do notsleep at all during the first month of life. They are active 24hours a day -- and their mothers have learned to cope.

"Somehow these seafaring mammals have found a way to copewith sleep deprivation, facilitating rather than hindering acrucial phase of development for their offspring," Dr JeromeSiegel, a neuroscientist at the University of California - LosAngeles (UCLA), said in a statement.

Siegel and his colleagues said the developmental patternthey discovered in the dolphins and whales is different fromall other mammals.

As the calves of both species grow, their sleep graduallyincreases to adult levels.

"Their bodies have found a way to cope, offering evidencethat sleep isn't necessary for development and raising thequestion of whether humans and other mammals have untappedphysiological potential for coping without sleep," Siegel said.

The scientists, who reported the findings in the journalNature, believe the newborns' lack of sleep has severaladvantages. Their constant movement reduces the danger frompredators and helps maintain their body temperature until theydevelop greater mass and blubber.

It also enables them to swim to the surface frequently tobreathe and helps their body and brain to develop.

The scientists observed two adult killer whales and theircalves at SeaWorld in San Diego, California and four dolphinsand their offspring at the Utrish Marine Mammal ResearchStation in the Black Sea region of Russia for five months afterbirth.

Source: REUTERS

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