There is evidence to suggest that dogs do in fact dream. Like humans and many other mammals, dogs have a brain structure called the hippocampus, which is involved in memory and learning. Additionally, they exhibit similar sleep patterns to humans, including periods of Rapid Eye Movement (REM) sleep, which is associated with dreaming.
During REM sleep, dogs often exhibit various behaviours that are indicative of dreaming. These behaviours can include twitching, paddling their legs, making sounds, and even showing facial expressions that resemble those they make when they’re awake and engaged in activities. These behaviours are thought to be connected to the dog’s dreams, where they may be reenacting or processing experiences from their waking lives.
Research conducted on rats and other animals has shown that the brain activity observed during REM sleep is similar to the brain activity while they are awake and engaged in the same activities. While direct studies on dog dreams are more limited due to the difficulty of interpreting their experiences, the similarities in sleep patterns and behaviours between dogs and other mammals suggest that dogs likely do dream.
So, while we can’t be certain about the content of their dreams, it’s reasonable to assume that dogs experience some form of dreaming based on their sleep patterns and behaviours during REM sleep.