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There are dozers, dreamers, nappers and hardcore dead-to-the-worlders. Prepare to snuggle up with this gaggle of amazing comatose creatures.
There are as many different types of sleeper as there are animal varieties on the planet.
Some somnambulant strategies are based on protection, others on environment or even their particular characteristics. Some are just plain odd. Prepare to snuggle up with this gaggle of amazing comatose creatures.
Dolphins face a bit of a problem as they spend their whole lives in the water, but as mammals they need to breathe oxygen to survive. How do they juggle this when unconscious? Dolphins shut down half of their brain, which rests, while the other half is alert and looking out for any potential hazards. As they do this, the dolphin will lie on the surface of the water in a behaviour known as ‘logging’.
It was always thought that whales also engaged in this ‘brain half asleep’ behaviour. They may well do, but researchers discovered something extraordinary about the sleep habits of sperm whales. They came across a group of them completely asleep and bobbing vertically in the water like a strange aquatic forest of cetaceans. The whales didn’t react as the scientists approached them and seemed completely oblivious until a boat nudged one, at which point they all awoke and fled.
We’ve all seen the adorable pictures of sea otters holding paws while asleep to ensure they don’t float away from each other. Just in case they’re concerned about the grip of their aquatic counterparts, otters also anchor themselves to each other with seaweed. As many as 100 otters have been spotted floating in the ocean, wrapped in kelp, like some giant furry raft.
Elephants only manage about two hours of sleep per day, and that’s not even a concentrated block of shuteye. They tend to nod off for a few minutes at a time throughout the day. Possibly because of this, most of their sleeping is done standing up, with just the occasional recumbent slumber. Interestingly, captive elephants, with no predators or poachers to worry about, sleep many hours more.
Of course spiders have to be awkward. Even though animals sleep in a vast array of different ways, all of them, even bacteria, adhere to a 24 hour cycle, known as a circadian rhythm that is dictated by the rotation of the Earth. But scientists have discovered that certain types of orb-weaving spiders simply don’t bother with this. Their body clocks follow a 17, 18 or 19 hour cycle. Scientists aren’t exactly sure how the spider can even exist with this completely different body clock.
One problem with trying to work out a creature’s sleeping habits is the difficulty of identifying what is actual sleep. It’s easier to study captive animals, but they can behave in a completely different manner to their cousins in the wild. Koalas studied in zoos were thought to sleep for up to 22 hours a day, but a more detailed study, looking at animals in the wild too, revealed that they in fact sleep for around 14 hours a day plus a healthy amount of resting on top of that. Their diet of eucalyptus leaves takes a lot of time and energy to digest.
Perhaps you’re one of those people that claims that they can sleep anywhere. If that’s the case, then you are very walrusy in your habits. It’s been discovered that walruses have the ability to sleep just about anywhere, even in the ocean. They have been observed snoozing while floating on the surface, lying on the seabed and even bobbing along while anchored to an ice floe by a tusk, but they can also go for massive amounts of time with no sleep at all. It’s been reported that they are able swim for up to 84 straight hours without a rest.
Frogs are incredible. They have managed to master practically every environment on the planet, no matter how hot or how cold. They not only use hibernation in winter as a sleep strategy, they also engage in something called estivation, where they reach a dormant state during the summer months to avoid overly hot or dry conditions. Aquatic frogs hibernate underwater, while frogs living in arctic conditions manage to survive by using glucose as anti-freeze which protects their internal organs from the cold as they enter into a form of suspended animation. Despite all this knowledge, scientists aren’t sure exactly how frogs sleep during the months when they are active.
Featured image by © Tim Graham | Getty