Animal and Human Sleep: How Are They Usually Connected

Animal and Human Sleep: How Are They Usually Connected

by Bryn Fest

The Connection Between Animal and Human Sleep has long fascinated researchers. In this article, we’ll learn more about animal downtime, body size, and REM sleep. We’ll also look at the differences and similarities between human and animal sleep. You’ll discover why our bodies are alike and what makes them different. Read on to discover more. Here are some things to consider about animal sleep.

REM sleep

The first indicator of REM sleep in infant rats comes from the fact that they exhibit cycles of myoclonic twitching, similar to embryonic motility. The twitching occurs against a background of muscle atonia, a characteristic of early infancy. In infant rats, twitching and muscle atonia are coordinated, which suggests that they are in REM sleep.

REM sleep is also crucial to mammals. During this phase of sleep, mammals suspend their temperature regulation. While endothermy has evolutionary significance, it also requires a significant energy cost. Thus, some researchers hypothesize that REM sleep is closely related to endothermy. It’s not yet known what role REM sleep plays in mammals’ life cycles, but it’s important to note that both animals have different needs and functions.

  • Echidna and platypus

The echidna and platypus sleep patterns are very similar to those of mammals, although the echidna is unique in its lack of prominent motor activation during this sleep state. In contrast, the echidna sleep pattern does not have any evidence of REM sleep, and phasic motor activity is more recent. This lack of commonalities between the two species might explain why they have a similar pattern of sleep.


  • Chimpanzees

Chimpanzees are known for customizing their nests. While some of them spend their time building a nest daily, other chimps like to live a simple, minimalist lifestyle. Interestingly, chimps use their nests to sleep and relax. While humans use our beds for sleep, chimps prefer to use their nests for both. So, while we sleep at night, chimps are laying in theirs creating a perfect place to lay their head.

  • Patterns

Field studies have helped scientists understand the varying patterns of sleeping behavior in different animals. Using EEG and EMG recordings, researchers have been able to formulate hypotheses about the relationship between human sleep and bird nest-building. However, this method does have some limitations. First, a single camera cannot capture all the sites where a bird sleeps. In addition, the bird’s activity during the day might not be affected by sleeping in the nest box.


  • Neurons

Recent research suggests that the number of neurons in the brain affects the amount of sleep individuals experience. More neurons mean less sleep, which in turn means more time for feeding. Larger bodies can afford to have more neurons in their brains and a smaller amount of sleep time. However, the relationship between animal and human sleep and body size is not completely clear. However, this connection may be useful in understanding the differences between human and animal sleep.

  • Size of brain

The researchers used data from dozens of sleep studies to construct their model. They discovered that the number of sleep humans and animals get directly correlates with the size of their brains. While tiny humans have smaller brains than large mammals, their brains require more effort to grow. In both cases, the relationship between brain growth and brain maintenance is proportional. Sleep may even maintain brain size. These findings highlight how important sleep is for maintaining the size of a brain.

  • Ecological factors

Life history plays a role in mediating climate and urbanization on body size. Mammals with large bodies and good thermal buffers are more susceptible to warmer temperatures. Like sleeping is important for dogs. However, in urbanized areas, flexibility in inactivity times appears to be advantageous. Further research should consider these ecological factors. The findings will help us understand the effects of climate change on body size in humans and animals. And these findings will be useful in identifying how human and animal sleep patterns vary across different land uses.


The similarities between animal and human sleep are many and varied. Sleep is related to a wide range of processes, including memory consolidation, emotional stability, and brain homeostasis. The mechanisms by which sleep fulfills its functions are largely unclear, but it is clear that animal sleep evolved over alert wakefulness. Animals evolved this process over time and evolved it to meet the demands of their environment. The similarities between animal and human sleep go beyond a shared genetic makeup.

  • REM and NREM

Studies of animal sleep states have identified that mammals and birds are both subject to two distinct electrophysiological sleep states, known as REM and NREM. Despite this, the processes that occur during these states are distinctly different in both mammals and birds. Although the differences between animal and human sleep are largely minor, the similarities between them suggest convergent evolution. For example, mammals and birds are both thought to have evolved their form of REM sleep based on different criteria. There are many differences in animals and humans between REM vs deep sleep.

  • Brain activity

There are some similarities between animal and human sleep. Although mammals are more complex, animals like pigeons and ducks exhibit similar patterns of brain activity during sleep. Birds, on the other hand, lack the laminar arrangement of neurons in the neocortex, which would allow them to sleep. Hence, these animals do not need the neocortex to produce sleep rhythms, as it is unlikely to perform functions unique to the neocortex.


In the early days of comparative animal biology, researchers focused on the similarities between mammalian and bird sleep, aiming to answer the question “did mammalian and bird sleep evolve independently?” The differences, however, have been overlooked for decades, with little consideration given to their functional implications. After the shift from model-based thinking to experimentally-based observations, a framework was created to interpret the differences in animal sleep.

  • Sleep time

While humans need only about seven to nine hours of sleep per day, many other animals require much more. While the stereotype of the lazy sloth is based in reality, three-toed sloths need an average of 16 hours of sleep a day, while the two-toed variety requires just sixteen. Other examples of animals with similar sleeping patterns include the little brown bat, giant armadillo, and North American opossum.


The differences between animal and human sleep may be due to the differences between their physiological and behavioral processes. Human sleep is characterized by higher levels of REM sleep and shorter sleep duration than that of other animals. Human sleep is also described as more efficient than that of the animals that share their habitat. But how does this work? The answer may lie in the way we live. Our culture and environment also play a vital role. Moreover, the difference in sleep patterns between animals and humans may explain the varying phenotypes of our species.

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