Every pet owner has observed their beloved pet twitching, wagging its tail, growling, barking, meowing, purring, kicking and swatting at some point during sleep. Is it possible that they really are dreaming? According to many scientists, every mammal that has been studied, does experience some type of dreams. So, what do they dream about? That all depends on what has gone on throughout their day. The two major types of sleep experienced by all mammals that have been studied to date are the R.E.M. (Rapid Eye Movement) stage and the S.W.S. (Slow Wave Sleep) stage. These two sleep stages in mammals are extremely similar to that of humans. During these sleep stages, the brain processes all of the information it has absorbed up to that point in the day. In a sense, it is sorting files into individual mental folders for storage and reference. At a certain point during these sleep stages, dreams overtake the human brain. Seemingly, this happens in our pets as well. So, when your pet begins to make noises and movements as if he or she is chasing, being chased or just enjoying itself in general, it is most likely processing the events of the day and reliving the experiences it has had while awake. For an active kitten or puppy, everything it experiences is new and fresh. So imagine all of the excitement his or her little brain has to process every time a nap ensues. A lot of content in human dreams doesn't only come from daily events. Our imaginations play a large role in adding content to our dreams. People with active imaginations tend to have more intense and detailed dreams than others. Is this true for our pets as well? If you've ever watched your pet in the middle of playtime and wondered what all of the excitement was about, then you have your answer. They definitely have active imaginations. It has been proven that many animals experience a lot of the same brain activity during the R.E.M. stage as humans do. Our brains function the same in this sleep phase as they do when we are awake. With that in mind, it isn't hard to believe that animals really do dream like we do. So, the next time your dog or cat has had an exciting and unusual experience during the day, watch what happens when it is time to sleep. You may get to witness them reliving their day all over again in dreams.