You might have seen horses taking a nap while standing and wondering what other animals also sleep in standing position. Here is the list of animals that can sleep standing up:
- Horse
- Elephant
- Zebras
- Flamingos
- Giraffes
- Cows
- Camels
- Sheep
- Many birds such as Mallard Ducks
Some of the animals such as cows and camels have the ability to sleep standing but they prefer to lie down. Now you must be thinking why these animals sleep standing? Why can’t they just lie down similar to humans?
Why these animals sleep standing?
The primary reason for these animals take nap while standing is to protect themselves from the predators. You might notice that most of these animals are heavy and big animals and it takes a lot of energy and time to stand up and start running. Hence, lying down for sleep will make them vulnerable to the attack by their predators. Therefore in order to conserve energy and escape from the predator’s attack, most of them sleep standing. This does not mean that they don’t lie down at all for sleep, actually they have to lie down on the ground for rapid eye movement (REM) sleep. These animals take REM sleep by lying down because REM sleep can cause atony which is a state of paralyzed or extremely relaxed state of skeletal muscles in REM sleep. In simple words, muscles lose their strength in REM sleep mode.
Apart from escaping from predators, it is important for herbivore animals to take sleep standing so that they can easily digest the food. The diet of these animals usually includes tough cellulose which is difficult to break down and takes a lot of time. Taking a nap while standing helps them to continue this digestion process even when they are sleeping during the night.
According to research, big animals such as elephants sleep less compared to smaller animals and also they can’t sleep for a long time by lying down because it might cause damage to their internal organs. However, they too lie down to take REM sleep but not often like us.
These animals such as camels can lie down and take long naps similar to humans if they feel safe and secure from predators.
In the case of flamingos, their natural habitat does not allow them to lie down and sleep because the natural habitat of flamingos is caustic salt flats and therefore no place to lie down due to extreme alkaline conditions can cause damage to their body.
How these animals manage to sleep in a standing position?
These animals such as horses have the ability to align their legs vertical such that they stand without using their muscle power. After aligning the legs vertically, their knees will get locked allowing them to stay in that position for a long time without requiring muscle effort. These animals take advantage of these abilities to sleep while standing up.
Some of the birds have tendons in their legs that help them to clasp a perch while they are sleeping. Birds such as flamingos and ducks usually turn their head and tuck it into the feathers and pull their one leg to its belly before falling asleep in a standing position.
So we have learned that these animals sleep in a standing position for various reasons and they do lie down for getting REM sleep.
