When dogs and cats sleep, sometimes their mouths move and sometimes their legs kick... Of course, no dog or cat can tell people whether they are dreaming or what they dream... Here are two interesting experiments on animal dreaming.
A screen is set in front of a monkey, and the same picture appears repeatedly on the screen. Whenever this picture is shown on the screen, the monkey is forced to push a lever around him. If the monkey refuses to execute, it will be shocked. After a few days, the monkey formed a conditioned reflex: as soon as it saw the picture, it took the initiative to push the lever. Interestingly, later, the monkey would push the lever from time to time during sleep. This phenomenon shows that the picture that drives the monkey to push the lever appears in the monkey's sleep.
Another classic experiment was done by French physiologist posher noff with cats. There is a part of the cat's brain called "pons". If the pons are blocked by chemical or surgical methods, the cat will act according to the dream. Novov found that the cat after the operation suddenly raised its head in deep sleep, looked around, and then got up and walked in circles, as if looking for food. Suddenly, it raised its front paws, put its ears close to its head and pounced on the imaginary enemy.
Noff further observed the situation of two cats who had undergone surgery together. He found that the two cats who had been living in harmony suddenly had a fight in their deep sleep. Noff deliberately hit the objects next to the cat to make a sound, and even put the mouse next to them. However, the two cats remained indifferent to the surrounding situation and continued to attack their opponents. Nov believes that the two cats are fighting with their dream rivals.
These results suggest that animals also dream. Scientists believe that animals with a higher level of brain development will dream, and the quality of sleep with dreams is higher. Therefore, carnivores who can sleep comfortably are often more likely to dream than predators.
When people dream, they breathe shallow, their heart beats faster, their blood pressure rises, their brain blood volume doubles, and their faces and limbs twitch. At this time, the eye movement meter can measure the rapid rotation of the eye, and the fast wave must appear on the EEG at the same time. Therefore, generally speaking, "rapid eye movement" plus "EEG fast wave" can be used as a sign of dreaming. Using the above method to measure some animals, it is found that when frogs are asleep, there are only a few slow wave curves, and there is no "EEG fast wave" and "rapid eye movement" period. It seems that frogs can't dream. The tortoise has "rapid eye movement" and "EEG fast wave" when sleeping, but the time is very short, accounting for only 2% of the sleep time. Therefore, it is speculated that the tortoise's dream time is very short. Cats, dogs and monkeys dream. Dreams are longer. Monkeys are the longest, dogs are the second, and cats are the shortest.