Mermaids are a family of predatory aquatic vertebrates that use elaborate lures to attract prey.
While their precise classification has been greatly disputed, analysis of their feeding apparati has led to the widely accepted proposal that they are conodonts, members of a class that split from what would eventually become fish before the development of jaws.
Although mermaids are quite diverse, the overall layout of their body is similar:
They possess an elongate body similar to that of an eel equipped with more or less specialized fins depending on the species. The body ends in a primitive maw that, rather than a pair of jaws, uses a set of 13 bone growths each with rudimentary but very long and sharp teeth. Due to the lack of a jaw, the maw functions as a sphincter.
While most of their body is very simple and has remained mostly the same for about 250 million years, the most intricate part of the mermaids’ anatomy is the lure: inside their mouths, mermaids possess an elaborate muscular structure that might have evolved from a rudimentary tongue. The exact layout of that structure differs not only by species but also by individual within a species. All known mermaid species use this structure as a lure. While some species possess only simplistic lures that may imitate a flailing fish, other species use lures that even upon closer inspection resemble a human torso.
The lures are used to attract prey, either by appearing helpless and in need of help or by imitating easy prey. Once prey approaches and touches the lure, the mermaid uses the muscular lure to grab the prey, then retracts the lure into its mouth, dragging the prey with it. Mermaids’ feeding apparati very quickly cut into the victims’ flesh and tear it apart, leading to severe loss of blood.
There are 812 recorded species of mermaid, which are divided into five suborders. Most species of mermaid are highly specialized regarding their prey.
The largest suborder of mermaids are the Reedwight Mermaids. They inhabit shallow freshwater rivers, and reach sizes between eight and thirty centimeters. Most Reedwight Mermaids prey on small fish and amphibians, and possess lures that imitate insect larvae or fish. A notable outlier is the eponymous Reedwight Mermaid, that grows to up to thirty-five centimeters. Unlike its close relatives, it possesses an elaborate lure that imitates young waterfowl swimming on the surface of the river. When birds of prey attempt to attack the supposed easy prey, they are dragged underwater. Reedwight mermaids are found around the world, except in arctic climates.
In the tropical and tropical climates of Africa, another suborder of river-dwelling mermaids can be found, the Stormflood Mermaids. Stormflood Mermaids lay their eggs in the beds of rivers that dry out in the summer, and spawn when sudden rains flood not only the river but surrounding plains as well. They reach sizes between twenty and eighty centimeters, and largely prey on wading birds.
There is only one species of mermaid that lives in freshwater lakes, the Baikal Mermaid, which forms its own suborder. The bait on Baikal Mermaids strongly resembles a Baikal Seal. The seals have very few other natural predators, and the mermaids feed on nothing else, which leads to strong fluctuations in their respective populations depending on each other.
The fourth and most well-known suborder of mermaids are the Reef Mermaids, or True Mermaids. They are a very diverse suborder, with sizes ranging from thirty centimeter to three meters. Many species of small True Mermaids are ubiquitous in coral reefs, where they prey on fish and molluscs. Most famous, of course, are the species that prey on humans. There are thirteen recorded species that use human-like lures, ranging from smaller species whose lures resemble arms reaching out for help to large species that procedures articulated lures resembling human torsos. The most intricate lures possess rudimentary photosensitive eyes, functioning arms, and small openings through which the mermaids can blow air to produce whistling sounds.
The most mysterious suborder of mermaids are Abyssal Mermaids. There are, to date, only two described species of Abyssal Mermaids, but it is likely that there are more. Abyssal Mermaids spawn near the shore, and remain there until they reach adolescence. Until this point in their development, they strongly resemble Loreley, a species of Reef Mermaids with highly articulated false arms. They do, however, reach sizes up to six times that of Loreley, with the biggest observed specimen measuring in excess of fifteen meters.
Once they have grown up, Abyssal Mermaids begin diving deep into the abyssopelagic zones of the ocean. Although no live specimen in this stage of their life have been retrieved, observations suggest that they lose most of the articulate parts of their lures. It is unclear whether they continue hunting prey, as there are very few humans at the bottom of the oceans, but the existence of anthropomorphic anglerfish suggests that they retain their prey drive.
Abyssal Mermaids mate in the total darkness of the abyssopelagic zone, and have not been observed leaving it again. It is unclear for how long they survive after leaving the sunlight. Their eggs are encased in a sturdy shell and entirely round, and rise to the surface as they contain small bubbles of air.
