Contrary to popular belief, mermaids are not human or fish at all. They are mammals with the appearance of a human being above the pelvis and the appearance of dolphins or whales below. All mammals are warm-blooded and have hair, and all female mammals have mammary glands (breast and nipples for feeding young). Fish have a completely different anatomy. Mermaids do appear to have scales, but it is possible that this is in fact a pattern or camouflage that resembles scales. Some species of mermaid also have twin-tails and there are even some that are completely humanoid in appearance, apart from scale-like skin and dolphin-like biology (sonar, respiratory, circulatory and skeletal systems). The mermaid is also known to have both a Caucasian or Negro complexion and some sighted have a greenish appearance.
Mermaids have organs in their chest that can operate as a lung or a gill, depending on whether they are in or out of the water. The organ expands and contracts exactly like a lung, yet has the ability to extract oxygen from the water. This allows the mermaid to ‘breathe’ water in the same way that they breathe air – by filling and evacuating the chest cavity. This organ is also needed to operate the larynx. The human larynx cannot operate under the water as it cannot be made to vibrate from water pressure, yet the mermaids larynx operates equally well using water or air. The mermaid circulatory system is also designed to withstand differing water pressures like that of the dolphin and whale, while the skeleton is light and pliable like those of a bird or dolphin. The lenses of mermaid eyes are also different and are able to correctly focus for use both above and under water. A mermaid is also able to hear on a different level to humans and has the ability to use sonar for communication and hunting purposes underwater.
In mermaids, reproduction is much like that of dolphins. The reproductive organs of both the male and female are akin to the dolphin and whale, and mermaid babies are born live (as opposed to hatched from eggs).
The mermaid mostly eats fish, seaweed, and other edible things found in or near the sea. There are some species of mermaid that may feed solely on human flesh, but this has not been confirmed.
Mermaids can be found in large bodies of water a around the world. The mermaid is able to exist equally on land and in the sea, although it can become dehydrated if on land for extended periods of time. Most mermaids live in schools or pods, but some are known to travel as hermits.
Physical characteristics vary depending on habitat. The classic mermaid portrayed as having a torso similar to a modern model is found mainly in tropical regions while mermaids found in more temperate regions have a higher percentage of body fat.
Unfortunately, due to an extreme amount of hunting over the years the population has dwindled alarmingly and is now considered a highly endangered species.
The mermaid is a highly intelligent and extremely mischievous creature. This has allowed them to survive in even highly dived areas without being detected. For instance, the mermaids that populate The Great Barrier Reef have been known collect scuba equipment and donning them, imitate divers by showing only their upper bodies.