A man in China fell into a coma after spending a week looking for business ideas on the Internet without sleeping. Five months later, he was woken up by the smell of money.

In order to discover that penguins sleep more deeply in the afternoon, scientists crept up on sleeping penguins at different times of the day and poked them with a stick until they woke up.

The 1950s sleeping pill thalidomide, which caused 10,000 babies to be born with severe deformities, was tested on animals prior to its commercial release.

Lions enjoy relaxing and lazing around. They spend between 16 and 20 hours each day resting and sleeping. They have few sweat glands so they wisely tend to conserve their energy by resting during the day and become more active at night when it is cooler.