Every living organism requires sleep in order to function. Sleep brings about brain processing, storage of information, relaxation of the body, energy restoration, and tissue repair and growth. Sleep is important for babies as it is related to their mental and physical growth. There are two main stages of sleep. One is the non rapid eye movement (NREM) stage and the other is the rapid eye movement (REM) stage. The NREM stage is further divided into stage I, II, III, and IV. The NREM stage is also called the quiet sleep. In this phase, the sleep is light in the beginning and then proceeds towards a deep state. At this stage, the heart rate decreases, breathing slows down, and blood pressure drops. In the REM sleep, the brain is active. The heartbeats, breathing, and blood pressure increases. Most of the dreaming happens in the REM sleep stage. Studies demonstrate that newborns sleep a lot more than adults do. They also sleep in a different way from adults. A newborn needs 16 hours of sleep over a period of 24 hours. This sleep is not for a continuous period. Babies wake up and sleep a number of times during the day and sleep more during the night. They spend 50 percent of their sleep time in REM while the REM sleep phase for adults is only a quarter of their sleeping time. So while adults dream for only one or two hours, babies may dream for around eight hours a day. Yes, babies dream Sleep experts have shown that newborns dream the most in the first two weeks after birth. Babies spent most of their sleeping time in REM which is why they dream a lot. As dreaming takes place in a light state of sleep, newborns tend to wake up due to noises, movements, and other factors. When dreaming, newborns make a few noises. Their eyes move. They may move around the sides or vertically (up and down). Babies may laugh, smile, scream, or cry during the REM sleep. Also, their facial muscles, hands, and legs move, due to which they may wake up. Wrapping a baby in swaddling clothes can keep the baby's body from moving and help them sleep better. As babies grow, their body movement decreases when dreaming. Studies say that the brain activity associated with dreaming is essential for the babies' mental development. During the REM stage, the flow of blood to the brain increases. As a result, certain nerve proteins are produced, which are the building units of the brain. Babies get stimulation from what they see, hear, or feel. The brain processes the information acquired while awake, and stores what is essential to the individual. In 2010, a study concluded that babies learned while they were dreaming. Some scientists say that babies dream while they are sleeping in the womb. They perhaps dream about the sensations they experience while they are moving inside the womb. A fetus spends almost the whole time in a day sleeping. These sleeping hours are divided into deep sleep, REM sleep, and a time between them. When do they start dreaming? What is the time for babies to start dreaming? Researchers say that babies in the womb start experiencing REM sleep around week 25, and so may start dreaming at that point. On the contrary, some psychologists believe that children start having dreams when they are about five years old. At that age, they start becoming aware of themselves and begin to understand the things around them, which is what dreams are actually made of. What do they dream about? Sleep experts point out that babies cannot communicate what they dream about and do not have a clear understanding of the people or things around them. So, it is very difficult to know what babies dream about. Scientists presume that infants dream about infantile things like crawling around and pooping their pants, nipples, or images of people, plants, and animals. However, it is not clear what they dream about. Another question is whether babies go through nightmares. Neuroscientists think that babies, except the fear of strangers, cannot understand the meaning of fear until the age of two or three. Hence, they cannot have nightmares till that age. This was about whether babies dream and what they may be dreaming about. What goes on in their little heads while asleep, is really a mystery.