Theories of Sleep

Evolutionary Theory

• Webb 1989- suggested that sleep has evolved because it serves as some benefit to animals because the state of sleep is potentially dangerous
• The animals ability to get food, and shelter and the risk of predators it has reflects on how much it sleeps
• E.g Horse 2hrs : Many predators, lives in field, Lions 8/9 hrs: Low risk of predators, able to get food easier.

Supporting Evidence

• Dolphins: Dophins are the main supporting evidence for this argument.
• Dangerous for it to sleep due to it being a mammal, it sleeping runs the risk of drowning, endangering itself.
• Goes to extereme lenghts to get 8-12hrs of sleep
• 1/2 of brain sleeps at one time for 1 hr then awaks for 2hrs then other 1/2 sleeps.
• River Dolphins- Adaptations: but didn't elimate sleep.
• Overall state of sleep is dangers, putting animal's life at risks (unconscious yet…