Some ocean animals, such as whales,have to
swlm to the surface for arr. How do they sleep?
Surprisingly, they sleep by resting one half of ther “
brain and closing one eye. These annmals sleep for
5 several hours a day in all.
Migratory brds, such as cranes, also sleep in the
Same way as whales during their long flights.
However, the length of their sleep is not clear.
Would you like to sleep and do something at the
0 same time like whales and cranes? 1