The human brain attempts to make sense of our daily lives via the medium of dreaming. Our dreams tend to be a confusing combination of the real world and a fantasy land most of us know as 'dreamland'. We reach this place during the second stage of our sleep patterns. The first is known as 'slow wave sleep' (SWS) and the second is known as 'rapid eye movement' (REM). It is during the latter that we dream and if this period is interrupted or prevented, it can leave us agitated, anxious and irritable when we are awake.
Of course, we are not the only species with the ability to dream. Scientists have carried out intensive studies into the activity within the brains of other animals during sleep to discover if they dream and to ascertain an indication of what they may dream about. Known for twitching, barking or 'running' while they are sleeping, dogs are prime candidates for research.
Similarly to us, dogs have a particular sleep pattern in which they go through several stages. The first stage is known as SWS/NREM (slow wave sleep or non rapid eye movement), a very light sleep that is easy to wake up from. The brain is resting, but the dog's muscles are still prepared for use. The next stage, again similarly to us, is REM, which occurs during heavy sleep. Within this time, scientists can measure brain activity using an electroencephalogram. At the REM stage of sleep it records erratic activity at which point the dog may be moving, whimpering or barking.
This evidence suggests that dogs do indeed dream. In fact, all mammals are said to 'dream', though there are few theories about the reason why they do. It may even be for the same reason we do, but it is likely to be something we will never know for certain.
Interestingly, studies suggest that dogs don't suffer from nightmares. In fact, dogs that have been victims of neglect and abuse purportedly don't experience REM and therefore don't dream at all or dream very rarely. This is based on the theory that people who have been seriously abused or have faced severe trauma have a much higher chance of suffering from nightmares.
According to leading expert Dr. Ernest Hartmann, dreams are shaped by the emotions of the dreamer, so it therefore stands to reason that a dog may well dream about their family, their favourite activities or their favourite treat. Also, just like children dream far more often than adults, puppies dream far more often than adult dogs. Dreaming dogs must always be left to dream.