Do you ever wonder why humans animals sleep? Science reports have it that the reason for this hasn't been pinpointed yet. However, ongoing research postures many theories, frequently linked to either learning or memory generation.
As a Nature study suggested in 2019, probably, sleep helps restore DNA impairment in neurons. However, researchers found out that the upside-down jellyfish appears to sleep too, despite the brain and nervous system's absence. Therefore, the quest for the reason behind sleep continues.
What's commonly known is that, in essence, all animals do rest, although detailed studies have mostly occurred in mammals, as well as in birds.
Sleep style varies considerably across the animal kingdom. Whether you evaluate life in the African grassland, across the ocean, or high in Australia's trees, you'll certainly discover major disparities in sleep postures and the amount of rest needed daily in each species.
Furthermore, according to Columbus Zoo and Aquarium President and CEO Tom Stalf, basic survival has likely compelled different animals to develop their distinctive sleep habits. "It is about adaptation," he added.
Koala bears, animals considered native to Australia and are exclusively eating leaves from the eucalyptus tree, sleep from 18 to 22 hours each day.
How Giraffes Sleep
Giraffes, the tallest animals on earth, have frequently been touted as the mammals with the least sleep of all, despite their 3,0000-pound weight.
Statistic approximates giraffes sleep only half-an-hour each day. However, that's likely just citing deep sleep, considering information from a major 1996 study that pegged their total sleep nearly "4.5 hours per 24-hour period."
Reports on this finding have specified that part of the challenge in monitoring giraffes' sleep stems from their remarkably unusual sleep pattern.
This frequently occurs while standing, likely an adaptation to shield themselves from hunters since these long-legged animals are slow when transitioning from lying down to standing.
Other Animals' Sleep Behavior
The elephant is yet another animal considered to have the least sleep among mammals. According to research published in 2017, scientists who followed two free-roaming African elephants discovered the animals slept only two hours a day.
Like the giraffes, elephants frequently sleep standing up, as well. Explained Stalf, sometimes, these animals are seen leaning up "against a tree or something to take some weight off their body."
Like in zoos, sleep patterns in detention, where numerous studies are conducted, usually differ from real behavior in the wild. This, according to experts, can skew the numbers reported for the amount of sleep each species need every day.
Opposite the elephants and giraffes, male lions can sleep almost 20 hours each day. Females, on the other hand, snooze at least 15 hours.
Which Animals Are the Best Sleepers?
The Australian Koala Foundation said koala bears, animals considered native to Australia, exclusively eat leaves from the eucalyptus tree and sleep from 18 to 22 hours each day.
Another species known to be best sleepers are North America's brown and black bears. They are famous for resting, reportedly, for "a maximum of eight months straight while hibernating." Stalf said some of these animals are not active for a whole season, and "it's amazing."
Try peeking underwater, and you'll discover that fish do sleep with their eyes open since they lack eyelids. Some, Stalf added, even show what scientists call "sleep swimming."
On the other hand, creatures such as dolphins are famous for their so-called "unihemispheric" sleep patterns. Meaning, 50 percent of their brain changes into "slow-wave processing mode," while the remaining 50 percent stays active.
Some scientists suggest this sleep behavior does not really meet the "definition of sleep" as dolphins are continuously moving. Therefore, the experts also said a case could be made that these animals do not actually sleep.
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