It’s not just us humans who need to sleep to regenerate our bodies and minds, animals also need sleep and regular periods of rest to recharge their batteries. But how exactly do animals sleep? Are animal sleeping habits comparable to those of humans or are there differences? How do our pets sleep and how do animals in the wild do it? We at billerbeck have summarised all the important information about animal sleep for you in this article.
The sleep of animals
Animals sleep for the same reason we humans do. Their bodies need to rest in order to recover and regenerate. The phenomenon of sleep has been observed by scientists in a wide variety of animals: from insects and reptiles to molluscs, fish, birds and, of course, mammals. There are some striking differences between the sleeping habits of the various animal species, but there are also some similarities.
Interestingly, there are also different sleep phases in animal sleep, such as REM sleep and non-REM sleep, which also includes lighter sleep as well as the deep sleep phase. Just like us humans, animals can also dream, as many will have noticed with their pets.
How animals sleep differently
While some animals only sleep for a few minutes at a time, others spend almost the whole day sleeping. The sleeping behaviour of animals differs from species to species, which has physiological reasons on the one hand, but can also be related to the respective habitat. This is because the time of sleep is also a phase in which animals are particularly defenceless. Many crawl into shelters to find peace and quiet. Others live and sleep in herds, packs or family groups, which brings with it a certain security.
In the following, we have listed the different ways in which animals sleep, using various, sometimes unusual examples.
How do birds sleep?
Migratory birds and seabirds, some of which are in the air for days or weeks and do not interrupt their flight during this time, sleep in stages while flying, and only for a few minutes at a time. This means that they do not get more than one hour of sleep per day in total, but make up for the missing sleep when they arrive at their destination or on land.
How do elephants sleep?
Elephants living in the wild also sleep in bites, often not lying down but standing up. Between four and five sleep phases of a maximum of half an hour are sufficient for the trunked animals. This is certainly due to the constant threat of attacks by predators, as zoo elephants allow themselves much longer rest periods and sometimes sleep for up to seven hours.
How do hedgehogs sleep?
Many small mammals, such as hedgehogs, are crepuscular and nocturnal. They spend the day sleeping in their nests and only become active towards the evening in search of food. Hedgehogs are awake for several short periods lasting a maximum of two hours each – usually in the early evening, around midnight and then again in the early morning – and roam their territory in search of food. In between, the hedgehog lies down again and again and sleeps. In total, hedgehogs sleep for up to 18 hours a day.
How do giraffes sleep?
Giraffes prefer to sleep in groups, usually standing up, because the lying position gives them a certain defencelessness. As the large herbivores have to spend a lot of the day eating, they only have about 2 hours a day to sleep.
How do lions sleep?
Everyone is probably familiar with the image of a pride of lions sleeping or resting in the African wilderness. In fact, the big cats of prey sleep for around 13 hours a day. In between, the animals rest in the shade under trees and doze off. This is partly due to the extreme heat and partly because lions need to conserve their energy for the strenuous hunt. They therefore rest for a large part of the day and are mainly active at hunting time.
How do fish sleep?
Fish sleep is characterised by reduced brain activity, a slow heartbeat and an almost complete lack of movement. Due to the lack of eyelids, fish sleep with their eyes open. Even during sleep, fish are always alert and react to threats – for example from predators – although not quite as quickly as during the waking phase.
How do whales and dolphins sleep?
As mammals, whales and dolphins must regularly come to the surface of the water to catch their breath. This is also the case during sleep, of course. Dolphins therefore use a special sleeping technique known as hemisphere sleep. The two halves of the brain alternate with sleeping – always in the rhythm of a few minutes. The half of the brain that is awake ensures that the dolphin regularly rises to the surface and breathes, while the other half slumbers peacefully. Incidentally, other animals, such as orcas and flamingos, also utilise half-sleep.
Sperm whales and humpback whales sleep upright in the water in groups. An impressive spectacle, as you can imagine. In these whales, the two halves of the brain do not alternate, but both sleep. The large marine mammals hold their breath while sleeping and wake up in time to catch their breath. Sperm whales like to sleep with their heads facing upwards a few metres below the surface of the water. Humpback whales, on the other hand, prefer to turn their heads towards the sea floor to sleep. Overall, these large whales sleep for around 1.5 to 2 hours a day.
How do horses sleep?
Horses – like many other animals – spend a large part of the day dozing. This state between sleeping and being awake can turn into real sleep, but does not have to. Horses often sleep standing up – locking leg joints prevent them from falling over – but then usually only lightly. Horses sleep really deeply when lying down. However, they only do this when they feel particularly safe, because as flight animals, horses are always in a guarded position. In total, horses sleep for around 3 to 5 hours a day, divided into several shorter sleep periods.
How do koalas sleep?
The cute koalas are real late sleepers. The Australian marsupials sleep for up to 21 hours. They spend the remaining three hours of the day eating. Their favourite low-energy food, the leaves of the eucalyptus tree, is the reason for this extremely relaxed lifestyle and forces the animals to act as slowly and quietly as possible. If you sleep a lot, you use less energy and the koalas have made this their motto.
Sleeping behaviour of domestic animals
In addition to wild animals, we are of course also interested in the sleep of our most loyal friends, our pets. Dogs, cats and budgies are part of our everyday lives, day and night. That’s why it’s particularly exciting for us to take a closer look at the sleeping habits of our pets.
How do cats sleep?
Cats like to sleep and rest a lot. This may be due to their history, because a wild cat has to conserve its energy as it needs a lot of energy to hunt. That’s why our domestic cats also spend a large part of the day sleeping and dozing, around 18 hours a day.
How do dogs sleep?
Dogs are also heavy sleepers. Adult animals sleep for up to 14 hours, or even more depending on their exertion and requirements. Dogs vary in their lying position. Some love to sleep stretched out on their back with all four paws outstretched. Others prefer to rest curled up tightly in a sheltered position. This is down to the animal’s personal preference.
How do budgies sleep?
Budgerigars spend around 10 hours a day sleeping, preferably in an elevated position on a perch. With its feathers fluffed up for optimum thermal insulation, eyes closed and sometimes with its head twisted backwards and hidden in its back feathers, the budgie slumbers away with pleasure.
