- There most be some need for sleep, because it is dangerous, if we didn't need to we and animals would have evolved to survive without sleep
- Suggests that sleep has survival benefits, keeps animals imobile- therefore if they sleep somewhere safe, they are safe from predators.
- Different animals need different amuonts of sleep, this reflects their need for food, methods of obtaining food and exposure to predators.
Animals Average amount of sleep (% per day)
Brown Bat 82.9%
Human Infant 66.7%
Golden Hamster 59.6%
Human Adult 33.3%
Animals and Sleep
Animals sleep for shorter periods if they:
- are at risk from predators.
- cannot find safe places to sleep
- high metabolic rate- need slots of food
- Animal- Cattle, sheep, horse.
Animals sleep fr longer periods of they:
- Can easily find safe places to sleep
- Predators/Have few Predators.
- Satisfy need for food and water quickly
- Animals- Lions Tigers