If you feel like you were hit by a bus after 4 hours of tossing and turning throughout the night, just imagine what life must be like for a seal. Seals officially win the title as ‘the worst sleepers of all time’, at least by human standards. Seals only sleep for roughly one and a half minutes at a time. In addition, they sleep with only half of their brain, while the other half keeps them swimming and near the surface. This is thought to be an evolutionary trait brought on by their inability to breathe underwater and the threat of predators.