Humans may rule the Earth, but the world is full of amazing animals of all shapes and sizes, and we're only just starting to learn how truly remarkable they are.
When it comes to sleep, scientists still don't fully understand the ins and outs of it. We know that sleep is an essential part of life (total sleep deprivation leads to death), but we're still unsure as to the reasons why sleep is so important.
How Animals Sleep
Studying the various different sleeping habits of other animals, can help scientists crack the puzzle of sleep.
Did you know that certain marine animals can sleep underwater? And that some migrating birds can fly for six months straight without ever touching the ground? check out the infographic below for more amazing facts abaout how animals sleep.
Animal Sleeping Facts Explained
Dolphins and whales have the ability to sleep with only one-half of their brain at a time. This prevents them from drowining in their sleep.
The method is known as “logging” and it has been observed in bottlenose dolphins. During sleep, the bottlenose dolphin shuts down only half of its brain, whilst the other half remains ‘awake’ at a low level of alertness.
This allows the dolphin to retain control of their blowhole (through which they breathe), preventing them from drowning. An extract from an article in Scientific American:
Although still a matter of discussion, most researchers feel that in order to breathe, a dolphin or whale must be conscious and alert to recognize its blowhole is at the surface.
Sea Otters will sometimes hold hands when they sleep so they don't drift away from each other.
Sea otters often eat, rest, and sleep together while floating in groups called rafts. A raft may have a few otters, or hundreds! Rafting sea otters sometimes “hold hands” to stay together.
Giraffes can go weeks without sleep. Being large and rather slow animals, they're constantly vulnerable to attacks from predators, and therefore cannot sleep for long periods.
Giraffes have developed some pretty unique sleeping habits, and sleep the least of any mammal.
When they're young, giraffes lay down to sleep, tucking their legs underneath their bodies and curling their heads round to rest on their rumps. However, adult giraffes in the wild barely get a chance to sleep in such luxury; and are forced instead to sleep standing up in short bursts. In fact, they almost never sleep for longer than 5 minutes at a time.
Migrating birds can sleep whilst flying. Some species of birds fly for 6 months straight migrating, drinking and sleeping whilst airborne.
Scientists have found that migrating birds can fly for 200 days straight, eating and sleeping while soaring through the sky.
The Alpine swift was studied by a group of scientists in 2011, and it was discovered that they appeared to fly nonstop.
The swifts eat bugs in mid-air, so that explains why they don't starve. But the results "raise the question of how or whether these birds sleep". The swifts activity appeared to raise and fall during flight, and the researchers speculate that the birds might still be able to control their flying while sleeping. The team concludes that "swifts do at least to some extent sleep while airborne." - Conservation Magazine
Cows like to sleep close to their families, and sleepng arrangements are determined by individuals' rank in the social hierarchy.
Cows are actually very intelligent, and have a social hierarchy with a ‘boss’ cow. Any cows that don’t follow the leader become isolated from the herd.
Horses, Zebras and Elephants can sleep standing up. This is because they are 'prey' animals, and need to remain alert in case they are attacked.
Horses, zebras and elephants are just 3 examples of animals that can sleep standing up, because it allows them to quickly escape an attack by a predator (the process of standing up can be slow and clumsy).
However, horses, zebras and elephants will lie down when they require REM (Rapid Eye Movement) sleep. Typically, the amount of REM sleep they require is very small, so they don’t need to lie down often.