Newborn dolphins do not sleep
2005/09/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
Among mammals, cetaceans form a very special group. Although some particularities are evident, little by little zoologists are discovering others. For example, American zoologists have found that dolphins and newborn orcas spend a month without sleep. In most mammals the opposite happens, man is a clear example of it; in the first month of life the young sleep a lot to help the body develop properly. The opposite happens in dolphins.
For adult dolphins, the brain is replaced by a single hemisphere. In newborns do not sleep. Not sleeping has some advantages. On the one hand, it allows to escape from predators in an unprotected sea and, on the other, helps the body not to lose heat while forming layers to the cetacean. But not sleeping also has some serious disadvantages. Sleep is necessary in other mammals and not only in the case of offspring. There has been the death of laboratory rats without letting sleep. It also causes serious harm to humans. That's why scientists don't understand how dolphin chicks get no harm during this first month of life.
Zoologists have little doubt. It has been proven that newborn dolphins do not sleep — because when breathing they are very frequent — but it would be advisable to measure the brain activity of the offspring to better investigate the subject of sleep.
