A mermaid is a mythical creature with the upper body and head of a woman and a fish’s tail. They have appeared in folklore around the world and are known everywhere from Ancient Greece to the extensive Hinduism. Whether they are delightful, alluring women who seduce forlorn sailors into their enchantment or deadly monsters that pull men to their doom, they have always been seen as mysterious and beautiful.
One of the most important questions regarding mermaids is where do they sleep? Mermaids are half-mammalian and half-aquatic creatures, so it is possible that they morph into their human form when they sleep. However, this would require a lengthy process that could be dangerous or uncomfortable, so it’s more likely that they sleep similar to underwater mammals such as dolphins, seals, and whales. This means that they sleep with only half of their brain active at a time.
Generally, most stories that involve mermaids depict them sleeping on seaweed beds or giant stones that either have or don’t have seaweed on them. There are also a few stories that portray them in underwater or island caves, but this is much less common than the two other options mentioned above.
No matter where mermaids sleep, they do so underwater, as most of their anatomy is adapted for this environment. It is also very possible that they breathe through gills, similar to a fish, while their mouth, nose, and lungs allow them to breath above water.