Imagine waking up in the morning after a good night’s sleep. Your thinking is sharper, your memories are clearer, and you may even feel a lot happier about the day. Every organism studied by scientists has a period of sleep, although requirements for duration and physiological patterns may differ between species. Sleep is critical for memory, thinking, and physical health. Diseases or disorders that cause loss of sleep or changes in sleep patterns often lead to health problems. Our bodies let us know when we aren’t getting enough sleep and we all intuitively understand that sleep is important, but have you ever wondered exactly why humans need to sleep?