Rae Scheder, age 10, of Visalia, Calif., for his question:
DO FISH EVER SLEEP?
Dogs and cats sink into dreamy sleeps, more or less as we do. All the other animals must take rest periods from time to time, though many of them do not sleep as we do. For example, the average fish takes one or more daily naps. But there is evidence that he does not dream and his rest period cannot be classed as true sleep.
When a person falls asleep, the muscles relax, the breathing and heartbeat slow down and the senses lose touch with surroundings. We have known these facts for ages. But recent studies have revealed what goes on in the sleeping brain, also when it is likely to dream. This was done by measuring the electrical waves that the brain puts forth continuously. During waking hours, 10 small brain waves occur every second.
During the first two or three hours of normal sleep, these brain waves are longer and slower Then there are several periods of faster waves and rapid eye movements. This is when the sleeper dreams.
The same methods have been used to test the sleepingpatterns of a vast assortment of animals. When the average fish takes his rest period or a daily doze, his brain wave patternsdo not change as ours do. True, his body processes slow down and his senses become less aware of his surroundings.
However, his brain waves give no indication that he does any dreaming, either pleasant or otherwise. What's more, since his eyelids are transparent and sealed shut, he seems to doze with the same glassy, wide open stare.
Many fish are most active at night, when schools of them.swim their fastest to escape their enemies. During the day, they slow down and take perhaps several rest periods. Many fish retire to hideaways in rocks and coral reefs to take .their daily naps. A goldfish is likely to doze near the bottom of his bowl.
Amphibians also take dreamless dozes like the fishes. Their body processes slow down and their senses become less aware of what goes on around them. Usually these half sleepers retire to sheltered spots where they can nap undisturbed but they do not enjoy the dreams of true sleep.