Although it may seem completely unnatural to people (although it is possible), sleeping while standing up is more common with wild animals.
Be it because they can’t bend down or because they have to be ready to run – here are the 10 animals that sleep standing up!
- Wild and Domesticated Horses
- (Many) Birds
- African Buffalo
1. Wild and Domesticated Horses
Scientific name: Equus ferus & Equus ferus caballus
Both wild and domesticated horses show the ability to stand up while sleeping. They’re capable of sleeping while standing up because of something called ‘the stay apparatus’.
This group of ligaments, tendons, and muscles locks the animal in place and allows them to sleep without moving.
Although horses sleep standing up, they can also sleep lying down if they want to. Horses generally don’t sleep much – up to two hours a day, so they don’t spend much time sleeping while standing up.
Cattle have also developed the stay apparatus, but they rarely use it for sleep. Instead, they use it to rest a limb while grazing and they switch from limb to limb in order to rest.
Horses use this ability to stay wary of predators and ready to run at any time. As we’ll see in this article, this ability is very common with ungulates and almost every single ungulate species can sleep standing up.
This doesn’t apply to all ungulates, though, as bison and deer haven’t been spotted sleeping while standing up.
Scientific name (family): Elephantidae
Elephants are known to doze off while standing up, usually while resting under trees. However, they complete the full sleep cycle by lying down. Elephants can sleep up to four hours per day.
These massive animals find it difficult to stand up once they’re lying down, and they doze off standing up for the same reason giraffes do. It’s also possible that they could hurt their organs by lying down, which is why elephants sleep standing up sometimes.
Scientific name (genus): Giraffa
The answer the ‘do giraffes sleep standing up’ question is complex. Giraffes sleep for about 4.5 hours a day and they combine sleeping upright and sleeping laying on the ground. Since they’re such tall animals with long legs, getting up from the ground is difficult for them.
Additionally, if they get ambushed by predators while they’re sleeping, their chances of survival are significantly reduced. However, if the giraffe is just taking a standing nap, then it can just come to its senses and start running.
Standing sleep is more common in older giraffes, presumably because it’s easier for younger animals to get up from the ground.
Scientific name (family): Phoenicopteridae
Even though most birds sleep while standing, flamingos are a bit different. These birds are known for their incredibly long, giraffe-like legs, and bending down is difficult for them. To avoid this problem, they usually sleep standing up.
On top of that, flamingos have a very long neck that allows them to observe the space around them with ease. That way, if they’re woken up by the noise, they can just look around and flee from predators if necessary.
However, if they slept lying on the ground, this would be impossible as they would have to get up first.
5. (Many) Birds
Scientific name (class): Aves
Birds might be the most effective sleepers in the animal kingdom as it’s become apparent that they can sleep while flying!
When they’re on the ground, though, they commit to vigilant sleep – they sleep, but they wake up every now and then for a quick peek to make sure they’re safe, after which they return to sleep.
A lot of bird species (including the previous entry) are known to pull one of their legs inwards to protect it from the cold. Birds that live in flocks, like ducks, will stay standing while sleeping up.
This is especially important for the birds on the outer lines of the flock as they’re the first ones to notice predators. Since birds can fly, all they have to do when they notice a predator is to fly away.
6. African Buffalo
Scientific name: Syncerus caffer
Buffalos sleep standing up mostly to stay vigilant. Despite their size and power, predators could easily get the upper hand on the buffalo if they caught a buffalo sleeping.
In order to rest completely, buffalos still have to lie down to sleep. However, they take their short naps standing up.
Scientific name (genus): Camelus
Camels can sleep up to 4 hours per night (but usually less than that), and they spend most of their sleeping time on their knees. However, when they doze off, they’ll stay on their feet safely by using the stay apparatus.
The actual sleeping position of camels is interesting – they get down on their knees bent and their legs folded beneath the body. They extend their neck and simply drop their head to the ground.
Scientific name (genus): Gazella
Although gazelles are often seen lying down to sleep, they can also sleep standing upright. Since they sleep in very short intervals of only five minutes, it makes little sense to lie down and get up every single time.
Despite what’s posted online – there is no scientific evidence supporting the claim that gazelles can sleep while they’re running.
Scientific name (family): Rhinocerotidae
Rhinos can sleep both on the ground and standing up – this depends on the length of the sleep. These animals can sleep up to 8 hours a day, mixing longer and shorter intervals.
When sleeping in shorter intervals, rhinos will stay standing up because getting down is difficult for them. They’re large, heavy animals, but their legs are short for their size, and getting up and down is exhausting.
Scientific name (genus): Hippotigris
The final entry on this list is the zebra, which can sleep up to seven hours a day. Zebras sleep standing up during the day as they usually sleep in short intervals. However, they sleep for longer during the night and they lie down for that.
Just like horses, they simply lock their legs in and they know that they won’t fall.
Obviously, not all species of animals are included on this list (there are hundreds of birds and ungulates capable of sleeping while standing up), but there are the most important and the broadest groups of animals that sleep standing up.
In most instances, this is defensive behavior that allows animals to quickly run after being disturbed by predators (notice how not one animal on this list is a predator). In some cases, like those of elephants and giraffes, getting down to sleep is actually difficult and staying up while sleeping is simply easier.