There were only two animals on earth who made attempts to directly tell people about their dreams. These were the gorillas Koko and Michael. Penny Patterson, the “educator” of both gorillas, wrote that Coco sometimes talked about events that never happened, invented people and places, and such stories were heard shortly after Coco woke up. Michael, who was taken to the zoo after poachers killed his entire family, sometimes woke up saying “Bad people kill gorillas.” All other hypotheses about what happens in the brain of animals during sleep are just speculations of scientists.
However, scientists know that the brain of most mammals goes through the same cycle during sleep as the human brain, from falling into deep sleep to REM sleep, when the brain is more active. Hence the assumption is born that many other animals can dream. Small animals (for example, mice) go through these stages quickly; in large animals, the cycle is sometimes longer than a human. Reptiles and fish sleep without REM sleep, which is why scientists believe they are not dreaming.
People have dreams about what interested and worried them before going to bed. There is no reason to think that things are different with animals. Dogs are very attached to their owners, which is why Dr. Deirdre Barrett suggests that dogs reproduce the face and smells of the owner in their dreams.
A little more is known about cats’ dreams thanks to the research of Michel Jouvet. The scientist destroyed a tiny area in the cat’s brain that limits muscle movement during REM sleep. As a result, cats, falling asleep and entering REM sleep, got up, jumped, stretched and hissed – in short, they behaved as if they were hunting in their sleep.