It long seemed as if African elephants were the champions of the all-nighter. They can get by on about two hours of sleep. Other mammals need much more, like koalas (20 hours) or you (at least seven ...

How can an air-breathing animal sleep safely in the open ocean, with killer whales and great whites prowling near the surface? For elephant seals, we now know the solution is to dive around 100 metres ...

During the many months they spend at sea gorging on fish and squid, the massive mammals sleep only about two hours a day. By Annie Roth It long seemed as though African elephants were the champions of ...