This article was originally published on January 22, 2020.
We know that animals can sleep, but can animals dream like humans? Believe it or not, they do dream.
We humans have sleep patterns. Our brain cycles through 5 different phases during sleep. Stage 1, 2, 3, 4 and 5th and the final phase is called the REM sleep.
REM stands for rapid eye movement. This REM sleep takes around 25% of your sleep cycle and occurs 70 to 90 minutes after you fall asleep.
During REM sleep, our brain and body get energized which makes us dream. But we still don’t know much about this mysterious connection between REM sleep and dreams.
REM sleep begins when signals from different parts of the brain are received by the brain’s cerebral cortex. The cerebral cortex is responsible for learning, organizing information and thought process. Signals are sent to the spinal cord to prevent body movements causing temporary paralysis of body muscles. This prevents you from moving while you are dreaming.
Animals have similar sleep patterns like humans. Animals have these REM sleep cycles too. Recently, scientists documented REM sleep cycles in reptiles . Mammals, birds and reptiles. They all can dream like us. Sleep-like states in cuttlefish  have been observed and studied.
This makes us wonder, what do they dream about? How cute their dreams would be? We still don’t know what they dream about as they cannot express their dreams. If they can dream, then they can have nightmares too.
Ever seen a dog or a cat make weird noises and move its body while it is asleep? That’s because it is dreaming. And by observing these kinds of behaviours, we can guess whether it is having a good dream or having a nightmare.
Next time when you come close to a sleeping animal, try and observe its behaviour to know whether it is actually dreaming or not.
1. Partial homologies between sleep states in lizards, mammals, and birds suggest a complex evolution of sleep states in amniotes.
2. A Preliminary Analysis of Sleep-Like States in the Cuttlefish Sepia officinalis.