How can you tell your sleeping dog is in the rapid eye movement (REM) stage?FamilyPet
Like humans, dogs have different sleep stages. Dogs fall asleep and enter into a stage of slow wave sleep. During this stage, a dog will be relaxed; his breathing will slow and his heart rate will decrease. Slow wave sleep lasts about 10 to 20 minutes, depending on the dog. After the slow wave sleep stage, a dog will enter into a REM (rapid eye movement) sleep stage.
You can tell if your sleeping dog is in the REM sleep stage because his behavior will be different from the slow wave deep sleep stage. During REM sleep, the brain is more active, which can cause the dog to roll his eyes under his eyelids, flutter his eyelids, have muscle spasms or twitches and make audible noises like barks or whines.
It is thought that during REM sleep, dogs may be dreaming. Since dogs have sleep cycles and stages that are similar to humans, dogs may dream during REM sleep, just as humans do. Adult dogs spend about 10 percent of their time sleeping in this REM sleep stage, while puppies spend the majority of their sleep time in REM sleep.