How do dogs sleep?

What is the dream for?

Rest is key for any species. Most animals have a biological rest-activity rhythm that allows them to restore their energy.

Sleep serves the dog to record his experiences and what he has learned during the day, among other essential functions. Sleep is important for the following reasons:

• It allows the animals' organism to conserve and restore its energy.
• Keeps the brain agile.
• Improves learning ability.
• It helps consolidate new memories and update old ones based on what the animal has just learned: the sleeping brain knows what new information is meaningful enough to keep and what is not worth retaining.
• Forge new neural connections.
• Allows growth: growth hormone is released during sleep, so understanding how dogs sleep and the importance of rest is essential when we talk about puppies.
• Prevents brain degeneration: during sleep, activity increases in the genes involved in the production of “oligodendrocytes”, which are the cells responsible for covering neurons with myelin, the “insulating material” of the brain. On the contrary, lack of sleep produces greater activity in genes involved in stress and cell death.
• Improves the immune system.

A dog that does not rest properly may have learning and memory problems, as well as a weaker immune system that leaves him exposed to diseases.

Keys to understanding how dogs sleep

Although it may seem contradictory to us, sleep is not a passive activity but rather an extremely active one. While a dog sleeps his brain is continually working.

During sleep, postural relaxation occurs and sensory thresholds are raised so that the dog can disconnect from the environment, so to speak.

Dogs, like humans, are polyphasic sleepers, which means they alternate different phases within sleep, one deeper than the other. Each of them has certain functions.

Polyphase sleepers

The dog's brain works based on brain waves, depending on what these waves are like, the dog will be in the waking or sleeping phase.

Dogs, like people, alternate phases of short wave or slow wave sleep and fast wave or REM sleep. To understand how dogs sleep it is essential to know what happens in each of these phases.

Within the dream we find two major stages or phases:

1. Slow, short-wave sleep or non-REM sleep
2. REM (Rapid-Eyes-Movement) Sleep

1. Slow sleep or NREM

During NREM sleep your dog's brain is calm and her body, although relaxed, may move or change position. Heart rate decreases, body temperature drops and growth hormones are released. During this phase of sleep the dog does not dream.

2. REM sleep (deep sleep)

During the REM phase is when the dog sleeps deeply and dreams. Breathing is rapid and irregular and the dog may agitate, move its legs as if it were running, and even make sounds and bark.

REM comes from the English phrase “Rapid EyesMovement” since during this phase of sleep the eyeballs move rapidly under the eyelids. Sometimes this can be easily observed by the dog falling asleep with its eyes slightly open.

The REM phase is the phase during which the dog dreams and captures a large amount of information from the environment due to its high brain activity. In this phase, in fact, the level of brain activity is similar to when the dog is awake.

Active rest postures and deep sleep postures in dogs

We talk about how dogs sleep, but we also have to keep in mind how they rest, even without being asleep.

Dogs adopt a wide variety of positions when resting and sleeping. Some of them allow them to be at rest but alert, and others help them fall into deep sleep.

During active rest, which is one that allows your dog to expend minimal energy while being alert to what is happening around him, your dog can be sitting or lying on his sternum. If it adopts a lying position, it will never be on its side because what the dog is looking for during active rest is to be able to react quickly to any unforeseen event or threat.

Dogs only sleep deeply and dream when they are lying on their sides, curled up, or on their bellies. They are postures that do not favor a quick reaction to a threat and are only adopted when they are absolutely relaxed.

Do dogs dream?

We have seen how dogs sleep but we have to answer the question of whether they can dream.

Given the similarities between dog and human sleep patterns, it would be strange to think that dogs can't dream. Now, it has not yet been possible to demonstrate what they dream about, although logic leads us to think that they recover experiences they have in their daily lives and, therefore, they dream about “dog things.”

Thanks to the study of encephalograms that analyze brain activity, scientists have shown that dogs dream and they do so during the REM sleep phase.

Do dogs have nightmares?

Just as we can affirm that dogs dream, we could deduce that dogs also have nightmares. In fact, at times we can observe our dog shaking during the REM phase as if he were very alternating and even vocalizing (barking and growling). Although today there is no scientific way to verify what images or stimuli the dog's brain is evoking during this sleep phase, everything indicates that dogs can have, just like people, unpleasant or unpleasant dreams and sudden awakenings due to of these nightmares.