Every animal sleeps. From gnats to gorillas, sleep plays an essential role in the health and function of almost every creature. Even migrating birds will sleep mid-flight! Most people have experienced the benefits of good sleep and the costs of sleeplessness. Unfortunately, humans are the only species that have significant trouble sleeping. But what is it about being human, or specifically a modern human, that can make sleep so fickle and elusive for some? What the Body Needs to Sleep Well What do we need to sleep like a dog? First, we need to feel safe. For sleep to occur, our nervous system must shift into the parasympathetic, or “rest and digest”, state. This is the opposite of the sympathetic, or “fight and flight” state. If someone is being chased by pack of hyenas, it is probably not a great time for a snooze. On the contrary, a lioness sleeping on the Serengeti surrounded by the safety of her pride can sleep regardless of the roaming packs. Safety is a relative concept, but an essential one for sleep. Secondly, we need darkness. Humans are ‘diurnal’ meaning that we typically like to be awake during the day and sleep at night....