Ever wondered what's happening in your dog's dream when it barks, twitches or growls in its sleep? Animal experts have evidence to suggest what the dream is about.
Dogs most likely dream about waking activities, such as being out for a walk, fetching a ball or running, according to MIT neuroscientist Matt Wilson.
Wilson studied the brain activity of rats during sleep. Rats' brains and sleep cycles are very similar to dogs' and humans'.
The researchers found that mice exhibited the exact same brain activity patterns when they were asleep as when they were running in a maze awake earlier in the test, suggesting they were dreaming about their experience in the maze.
Although a similar study with dogs has not been conducted, it is reasonable to believe that dogs, like rats, dream of things they experience when awake.
Check out our article about the benefits of sharing a bed with your pet.
You can compare cover from the best pet insurance for dogs in the UK.
Your dog might be learning in its sleep
Hungarian scientists examined the connection between sleep and learning in dogs in a study conducted in 2017. They found that, just like humans, dogs exhibited brain waves associated with memory, general intelligence and healthy aging during sleep.
The 15 dogs in the study were taught commands in English, a language they did not understand. Each study session was followed by a three-hour nap.
During their naps, the dogs exhibited bursts of activity during a type of slow-wave brain function that has been observed in humans and rats and is associated with memory consolidation. The more of these activity-bursts per minute dogs had the quicker they learned the commands.
How do we know dogs dream?
We have scientific evidence. We know that dogs exhibit Rapid Eye Movement (REM - a sleep phase where vivid dreams occur) and non-REM cycles when they sleep.
Researches studying dogs with an under-active pons - a centre in the brains that has parts that cause paralysis during REM sleep to prevent acting out dreams and sustaining injuries - can see dog's acting out their dreams.
Dogs have less active pons than humans and cats, so are more likely to move in response to what they're dreaming about. This is why they often, twitch or bark or, growl, or move their legs as if to run.
We also know that dogs spend less time in REM than humans do. It is thought that this is the reason why dogs need more hours of sleep than humans.
A 2016 study of sleep and resting behaviours in shelter dogs showed that dogs that slept more were healthier.
Do dogs dream in colour?
Contrary to popular belief, they do see in colour when awake, albeit in a spectrum more limited than humans.
So, if they can see colour in when they're awake, can they dream in colour, too, just like many humans do? It is impossible to know for certain.