A As any new parent knows, the first months of an infant’s life mean little sleep for the family. But humans have it easy compared to orcas, also known as killer whales. University of California, Los Angeles, neuroscientist Jerome Siegel and post-doctorate fellow Oleg Lyamin have found that for the first month after giving birth, killer whale mothers and their calves do not experience normal sleep at all, and neither stops moving for more than a few minutes at a time. “These sleep patterns contrast with those of most other mammals, which need extra sleep during infancy and gradually sleep less,” Siegel says. While orcas are never as active as in the first months of life, the young orcas’ movement and wakefulness help them keep their body temperature constant until mass and blubber insulation develop and allow for frequent respiration. Meanwhile, the mothers of newborn orcas must constantly look out for sharks, while teaching the calves to breathe.
B According to Siegel, the results of his orca study fundamentally change our view of sleep. “It has often been said that sleep is necessary for an animal’s primary development, particularly that of the brain,” Siegel says. “But here we have a creature which grows one of the largest brains in the animal kingdom, and yet it is doing this without sleep.” All mammals and birds “When you come downstairs at three in the morning, the goldfish isn’t lying on the bottom of the bowl, it’s swimming around,” Siegel says. But other scientists believe fish do enter a restful dormant state that is at least similar to sleep.
C Some animals die without proper sleep, and experiments have shown that sleep deprivation can cause death more quickly than food deprivation. Two weeks without sleep can kill laboratory rats. Sleep is clearly important, but what determines how much we sleep and when? Siegel thinks the sleep needs of an animal is dictated less by biological functions than by the animal’s environmental niche. Availability of food is a major factor. The long rest typical of bats, for example, helps the animals to economize on energy. “If a bat eats insects for only three hours in the evening, then maybe the best survival strategy is to reduce its use of energy for the rest of the day.”
D Sleep is not the same for all creatures. In dolphin’s half the brain may rest while the other half stays vigilantly awake, and the animal carries on everyday activities. Dolphins sleep literally with one eye closed - the eye on the opposite side of the body to the dozing brain hemisphere, since the right brain hemisphere controls the left eye and vice versa. However, for unknown reasons, closed eyes seem to be a virtually universal prerequisite for sleep.
E Neuroscientist Clifford Saper of the Harvard Medical School has located a small area at the base of the brain called the ventrolateral preoptic nucleus that sends chemical signals to other parts of the brain during sleep to slow those brain parts down and determines the best sleep target for the animal. It is flexible, able to reverse the normal nocturnal habits of a rodent to make it sleep at night, if day is the only time the rodent can find what it needs to eat. According to Saper, evidence suggests that for restoring tired muscles or any other body system, sleep is no more effective than a comparable period of wakeful resting - except for one critical organ, the brain. The human brain apparently cannot do without sleep. Studies show that prolonged wakefulness leads to degradation of memory, alertness, coordination, and judgment.
F Nevertheless, studies of species exhibiting ‘natural models of sleep deprivation,’ as psychologist Verner Bingman of Ohio’s Bowling Green State University calls them, may allow researchers to provide us with new methods for adapting to limited sleep without losing effectiveness. “We could live 20-hour lives instead of 12- or 14-hour lives,” says Bingman, who is studying the behavior of the migratory birds Swainson’s thrushes, which for migration purposes, go from a normal night’s sleep of 10 to 12 hours down to about 2.5 hours so they can fly at night. To handle the energy output of the long journey they must nearly double the amount of fat in their bodies. They have to switch from a diet of seeds to one of fruits and insects, which they must search for during the day, so further limiting their sleep time.
G Bingman and doctoral student Thomas Fuchs have discovered that during morning and midday hours the thrushes enter phases of drowsiness, during which they take as many as 50 micro naps per hour, most of them lasting about 10 seconds. When brain waves are measured, these napping behaviors look very much like normal sleep. Says Bingman, “The trick would be to develop techniques or drugs that could recreate a similar brain pattern in humans.” Saper, however, disagrees. “The trick would be to develop techniques or drugs that could create a similar brain pattern in humans.” Saper, however, disagrees. “The effect of 20 hours of wakefulness in our driving is the equivalent of two shots of whiskey,” he warns. “Sleep deprivation is unfortunately a major cause of death in the U.S among young adults, who have a very high crash rate between 3 and 6 am.” He thinks we are dreaming if we think we’re ever going to get by on as little sleep as newborn orcas or migrating thrushes.