Sleep is an important component of mammal's daily life and more so of newborn babies who in their first month of gestation are known to sleep for over 18 hours. However, it is different with some of the mammals living in the sea. It has been reported in Nature that newborn bottlenose dolphins and killer whales are wake most of the time in the first month. Their moms manage with only a wink or two than the newborns. This is perhaps because there are no safe places where an animal could curl up and rest and not worry about their predators. This maybe the natural response for their survival. Not sleeping also keeps them active and responsive allowing them to breathe oxygen at the surface and help them to grow more rapidly.
Conventionally it is believed that sleep is critical to early development. Most of the mammals so far studied sleep and rest after birth and only gradually decrease their sleep requirements as they grow. "Somehow, these seafaring mammals have found a way to cope with sleep deprivation, facilitating rather than hindering a crucial phase of development for their offspring," said Dr. Jerome Siegel, a neuroscientist at the University of California-Los Angeles and head of neurobiology research at the VA Greater Los Angeles Healthcare System.
Siegel has been studying animals to better understand human sleep disorders and the biological functions of sleep for the development of brain and other parts of the body. He reported recently that for humans, the eight hours or so of rapid-eye-movement sleep (out of about 16 hours total sleep a day) seems to be vital in fostering connections and development in the brains of infants.
Siegal said: "They have found a way to cope, offering evidence that sleep isn't necessary for development and raising the question of whether humans and other mammals have untapped physiological potential for coping without sleep."