Regardless of your preferred sleep mode, bats, elephants, frogs, bees, humans … we all have one thing in common: we all sleep. In fact, scientists have yet to find any creature that doesn’t sleep. But is sleep really necessary to survive?
Most humans will recognize that sleep is absolutely necessary. Scientists and thinkers dating back to the Greek philosopher Aristotle have since offered explanations for why we sleep, and yet the exact purpose of the dream remains an open question.
In the 1890s, Marie de Manacéïne, one of Russia’s first female doctors, was preoccupied with the mystery of the dream.
“We all love life and we all want to live as long as possible, but despite this, we sacrifice a third, sometimes even half of our life to sleep,” Manacéïne wrote on one occasion. In his quest to find out what exactly sleep is, he conducted the first sleep deprivation experiment on animals.
Using an approach that now seems quite cruel, the expert kept the puppies awake continuously, finding that they died after a few days from lack of sleep. In subsequent decades, other sleep deprivation experiments with other animals, such as rodents and cockroaches, found similarly fatal results. However, the underlying cause of death in these cases, and how it relates to sleep, is still unknown.
Big sleepers
While total insomnia seems dangerous, some creatures can survive with remarkably short bouts of sleep. They could be the key to understanding the function of sleep, scientists say.
A study published in 2019 in the journal Science Advances monitored the sleeping habits of fruit flies. They observed that some flies almost never slept. 6% of female flies slept for less than 72 minutes each day, compared to the average of 300 minutes for other females. Even one barely slept 4 minutes a day on average.
Is the dream less necessary than we really think?
In a 2016 study, another team of scientists in the Galapagos Islands equipped a group of birds, the common frigatebird (Fregata minor ), with a small device to measure electrical activity in the brain. The monitors showed that the birds in one of their hemispheres sometimes fell asleep as they soared over the ocean. Others even both hemispheres were dozing simultaneously in flight.
Sleeping while flying can be common among other species of birds, such as common swifts ( Apus apus ), which can fly for 10 months without landing, although scientists have no direct evidence for this. But perhaps more surprising, the researchers found that common frigates, while flying, slept an average of only 42 minutes a day, despite typically getting more than 12 hours of sleep on the ground.
Will we ever find an animal that doesn’t sleep?
Anything is possible, experts say. But everything seems to point to the fact that a minimum amount of sleep is essential to survive.
