This is how they sleep.......

Sperm whales sleep vertically. They have short naps for no longer than a quarter of an hour to charge the battery. This special phenomenon was first discovered by chance in 2007. At first it was believed that only one of both parts of the brain slept to stay alert and be able to breathe. This film shows otherwise. The footage is extremely rare. You have to approach the animals in complete silence, in order not to wake them up. Watch the film: