Birds do it, bees do it. Every creature with a brain does it.
Sleep, that is. While our human minds and sleep cycles are unique to our species, we share many features with our animal cousins. Not least being the circadian rhythms that can govern our sleep patterns, and therefore affect alertness and overall health. Scientists have long turned to animals in order to better understand sleep generally and, they hope, to better understand us. Here are five examples:
Fruit Flies & Sleep Patterns
The fruit fly is among the most-studied lab creatures, in part because the tiny insect is easy to raise and breeds quickly.
In 2000, separate groups of researchers from the Neurosciences Institute in California and the University of Pennsylvania used the fruit fly to define sleep in insects for the first time. The scientists found that the flies — like us — are harder to disturb when they are at rest, and that they need extra shut-eye the day after sleep deprivation. Fruit flies and other insects make it possible for scientists to explore the genes and molecular pathways involved in sleep.
Cats & REM
In the 1960s, French researchers used cats as a model to study the role of REM — the sleep cycle in which most of our dreams occur.
Although you may feel bad for the cats, the method was clever: Researchers forced felines onto platforms floating in water for up to 26 hours. The cats could sleep while standing or crouching, but during REM their bodies relaxed and they fell into the water. And, quite naturally, woke up.
After the experiments, the REM-deprived cats had narcolepsy-like episodes, suggesting the importance of the sleep stage in normal daily biological function.
Mice & Restoration
Why any of us need sleep remains a bit of a mystery. When humans and other mammals go through REM cycles, our muscles are paralyzed so that we don’t physically act out our dreams. It’s a vulnerable state, particularly if predators and other threats lurk nearby. And because sleep is widespread across so many species, evolution must have kept it for a reason.
In 2013, scientists from the University of Rochester Medical Center found one possible piece to the puzzle while studying mice. During sleep, cerebral spinal fluid cleared the mice brains of toxins, which means one of the main functions of sleep may be to help rid the brain of daily cellular waste.
English Bulldogs & Apnea
One look at a bulldog’s short snout and it’s no surprise that the pooch has trouble breathing. But even under that unusual façade, the bulldog suffers from abnormal anatomy of the upper airway, including an enlarged soft palate and unusually small windpipe opening.
In 1987, researchers found that these abnormalities make the animal a good model for studying sleep apnea — a disorder in which breathing gets interrupted several times a night, often by the tongue and soft palate obstructing the airway. Studying the animals, as well as subsequent research, may lead to new treatments for the condition.
Zebrafish & Melatonin
Melatonin is a hormone produced in the pineal gland in the brain, and it helps regulate our sleep and wake periods during our 24-hour circadian cycle.
In 2001, researchers from the Massachusetts Institute of Technology discovered that zebrafish — which are also used as a model for genetic research — use melatonin to reach a sleep-like state. The research suggested that the fish could help scientists study the molecular pathways for melatonin, as well as testing and discovering new sleep aids.