Bedtime for animals means lots of different things. From sleeping with one eye open to a leisurely 19 hour snooze; every animal species has different ways of getting their sleep.
You’ve heard of sleepwalking? Imagine sleep-swimming! Dolphins and whales spend their whole lives in the water, but just like people, they need air to breathe. When dolphins and whales go into a deeper sleep, only half their brain is actually snoozing. Part of them is still slightly awake as they drift along underwater. That way they can notice if predators are coming, and just as importantly, this part of their brains reminds them go to the surface every so often to get air. After a couple hours, the sleeping sides of the brain switch so the other side can get some rest too!
Photo by Chrissy Waiwright licensed CC BY-NC 2.0
Many ducks have mastered the art of sleeping with one eye open so that they can keep watch for predators. In flocks, the birds will often trade off who keeps watch while the rest get a full, two eyes closed, sleep. Birds that have long migrations, which may mean that they could be flying for weeks or months at a time, may be like dolphins and shut down part of their brains to sleep while flying (don’t try that at home!), or adjust their sleep habits so they can get by without sleep for long periods of time.
Horses do sleep standing up – but it’s a light sleep. Their legs lock them in place so they can doze off while standing, keeping them ready to dash off at a moment’s notice if something startles them. However for a deeper sleep, horses do lie down, but they only need to go into this deeper sleep for an hour or two every couple days.
Sea otters often float along the water on their backs while they sleep. But to make sure no one gets lost, otters will hold hands with their friends and family while everyone sleeps. They will also wrap seaweed and other plants around themselves to act as anchors so they don’t drift away.
Bears love to get their sleep in the winter – they’re out for months at a time! Most people call this long sleep hibernation, but bears aren’t technically hibernating. In true hibernation, animals will have their body temperature drop a lot, and the animals wake up every week or so to move around and eat something. Bears in their winter sleep only drop their temperature a little bit, and they don’t wake up at all – they can go 100 days without eating, drinking, or going to the bathroom!
The brown bat is the sleepiest of all mammals. They sleep for over 19 hours every day. They beat out cats at 12 hours, sloths at 14 hours, and possums at 18 hours. Plus they have a really cool way to sleep - upside down! Their feet cling to rocks or branches, while the rest of them dangles. Bats usually sleep in groups of bat friends and family. Sleeping upside down helps bats avoid predators, and it makes it easier for them to start flying. he bats just drop down, spread their wings and fly.
Giraffes win the wide-awake award for mammals that need the least sleep. In the wild they get less than 2 hours a day. They often do short power naps while standing, but when giraffes do settle down for some serious shut-eye, they fold their long legs to lie on the ground, and curl their necks around their bodies, making themselves into a giraffe-sized sleep ball.