- 12% of people dream in black and white. Before the introduction of TV, only 15% of people dreamt in colour.
- Two thirds of a cats’ life is spent sleeping.
- A giraffe only needs 1.9 hours sleep a day, while brown bats need as much as 19.9 hours a day.
- When dolphins sleep only half of their brains shuts down. The other half stays awake to help with breathing cycles
- The record for the longest period with no sleep is 11 days. This is extreme sleep deprivation and can be fatal.
- Within 5 minutes of waking up, 50% of your dream is forgotten. Within 10 minutes, 90% is gone.
- Pain tolerance is reduced by sleep deprivation.
- Humans are the only mammals that willingly delay sleep
- Scientists still don’t know and may never know if animals dream during REM sleep, as humans do