Siren

In human art, sirens are often depicted as birds with the heads of women or as creatures identical to mermaids. In reality, sirens look much more frightening than what pop culture depicts.

Sirens share a number of characteristics with bony fishes. Their entire body is covered in small, thin scales. Giving a siren a smooth appearance from a distance. What sets sirens apart from other fish is their distinctly human-like forelimbs. With a skeletal structure similar to land dwellers rather than lobed fins. The limbs are in a more forward position and located at a right angle to the body with muscles that allow for a great range of motion. The skeletal and muscle structures combined with robust shoulders give sirens the ability to prop themselves upright and pull themselves onto the beach. They possess a ribcage nearly identical to those of hominids. The fin rays of the forelimbs are greatly elongated and resemble the digits of human hands only lacking any sort of opposable digits. Articulation in these digits is limited only to swimming or grabbing motions and pulling its body across the shore. But the wrists are highly flexible and able to fully support the weight of the upper body. The head and neck of sirens are capable of a wide degree of lateral head movement impossible for other species of bony fishes.

To put it all this in simpler terms, the structure of the torso, arms, and neck of a siren bears a disturbing similarity to that of humans.

The head is also in a general hominoid shape, only slightly extended forward at an angle to allow for more hydrodynamic movement in the water. The jaw of a siren is "U" shaped and filled with sharp backwards facing teeth that prevent small slippery prey from escaping. The eyes are positioned higher up on the head and farther apart similar to those of crocodilians. Allowing sirens to peek above the surface of the water without exposing themselves. Sirens evolved the ability to blink independently from terrestrial tetrapods. Their eyes are located high on their head relative to other fish, and they blink by lowering their eyes as a membrane called the dermal cup rises to cover them. Although other fully aquatic fish species don't have the ability to blink, sirens did not evolve different muscles or glands to blink with; their blinking is accomplished with the same muscles in a different configuration. Rather than having specialized glands to produce eye lubricant, the fluid film on their cornea is likely composed of mucus secreted by their skin and water from their environment, possibly stored in the infraorbital space behind the dermal cup membrane. Sirens likely evolved blinking in response to conditions of terrestrial life, such as to keep their eyes wet out of water (they blink more frequently in high evaporation conditions and only when colliding with things in water) and to clean and protect the eye from debris, which may adhere to the eye or approach at a faster, more dangerous speed when in air versus when in water. Above its eyes are a pair of small knob-like protrusions. Adorning the side of its head are three pairs of small purple fins, with a massive horizontal crest-like fin on the top that droops down over the dorsal side. When seen from afar, this crest fin makes a siren look like it has the long flowing hair of a human woman. When swimming at high speed, these fins fold tightly perpendicular to the siren's upper body. The crest fin folds into a ridge down the middle like a tent to create a pseudo-dorsal fin. The arm-like pectoral fins also stay held flat against the body. When in this position, these fins help negates the effects of their humanoid upper body structure by reducing drag and giving the siren greater speed. Muscles in the base of these fins allow them to flex and fold when needed that, combined with slight adjustments in the pectoral fins, act as a series of rudders. Allowing a siren to make sharp turns or even abruptly brake to a stop in the water when flared completely out.

The rear limbs of a siren possess almost no adaptations that deviate from common bony fishes in the posterior of their bodies. Aside from the clavicle fins being slightly elongated and flatter on the interior sides to provide better stability when on land. Their body is torpedo-shaped like other powerful swimmers such as marlin and tuna fish. Ending in a powerful caudal fin powered by a large amount of muscle. Making sirens capable of amazing, yet short, bursts of speed. Sirens are cold-blooded and rely on the temperature of the seawater around them to maintain their body temperature. A dense network of blood vessels in their pectoral girdle, and under the ridges of their dorsal and caudal fins are capable of producing heat and allowing a siren to withstand colder temperatures outside of Artic conditions. Sirens breathe through gills located at the base of their necks and the anterior of the pectoral girdle. Sirens also possess a set of primitive lungs made of subdivided gas bladders. While not as efficient at oxygenation as the gills, these lungs allow a siren to breathe air for a span of three hours, before she will need to return to the sea. But the need to spend time on land allowed for the development of the siren's infamous ability: their song. A valved larynx in the throat allows the siren to close off its windpipe when in the water, but also act just like vocal cords. Only a siren's is startlingly advanced beyond any of a human's and shares many similarities to those of birds. Allowing sirens to create a multitude of different sounds.

Sirens are a mono-gendered species, with each member being female.

As a mono-gendered species, sirens reproduce asexually via parthenogenesis.

Although legends and eyewitnesses attest that they live in the coastal waters of the Mediterranean Sea, sirens prefer to spend most of their time in much deeper water. Some individuals may go their entire lives without being detected by a human being who lived to tell of it. They spend most of their time in the mesopelagic zone. Enjoying the warm temperate seas. However, in recent years their populations have gone into decline due to pollution.   Because they depend on saltwater to survive, they, like many oceanic monsters, are contained in the Depths. The flooded lowest reaches of the Trench facility. The much colder temperatures and scarcity of resources in the Depths have impacted the siren species greatly. Although their adaptations to thermoregulate have helped them cling to survival, it might not be enough. Given another year or more, the sirens held within the Trench may die out.

"First you will raise the island of the Sirens, those creatures who spellbind any man alive, whoever comes their way. Whoever draws too close, off guard, and catches the Sirens’ voices in the air – no sailing home for him, no wife rising to meet him, no happy children beaming up at their father’s face. The high, thrilling song of the Sirens will transfix him, lolling there in their meadow, round them heaps of corpses rotting away, rags of skin shriveling on their bones."

– The sorceress Circe warning Odysseus of the sirens as recorded by the poet Homer in The Odyssey, Book 12, lines 44-52.

  Sirens are opportunistic omnivores who feed on a mix of small fish, squids, seagrasses, and crustaceans. Their sharp teeth, powerful jaw muscles, grasping limbs, and adaptations specifically designed to lure and kill hominids, have made mankind their primary prey in modern times. When hunting humans, sirens will climb onto rocks in shallow intertidal zones and begin to vocalize. Mimicking sounds that they've heard from humans with disturbing accuracy. The most notorious one is that of women singing, but other common vocalizations include the chattering of sailors, cries for help from drowning men, and even the wailing cries of an abandoned infant. These sounds are all designed to elicit attraction or empathetic responses in any humans who may be in nearby watercraft. In some rare cases, a siren's song may put a human into a hypnotic-like trance. The ultimate goal of the siren's call is to cause a human to come and investigate the noise and potentially run their vessel aground or get close enough for the siren to snatch them from the boat and drag them into the water. Once a human is in the water, the siren will begin to pull them down, while attempting to bite off their fingers and toes to prevent them from treading water. Once the human has been drowned or dies of blood loss, the siren will begin to feed.   In the Trench, sirens have not fared well. Their reliance on saltwater to survive has confined them to the Depths. Few, if any humanoids would be able to survive the journey through the hellscape known as the Abyssal Prison above, let alone make it to the Depths and happen upon a siren. Thus, sirens have had to adapt and mimic the calls of other monsters in order to survive.

Sirens spend most of their time in the mesopelagic zone of the ocean and ascend the water column only to hunt during the night. While mostly solitary, they have been observed engaging in schooling behaviors. Like parrots, sirens can only mimic sounds that they've heard but have a higher learning capability, only needing to hear a sound once in order to replicate it. Interestingly, sirens seem to be incapable of learning new calls from other members of their species. Thus, young sirens just starting out on their own are attracted to loud noises and follow ships in order to learn new sounds from the humans on board.

Princesses of the Sea, Unloved by their Subjects

Despite being capable monsters and daughters of a primordial sea god, sirens do indeed have predators. Orcas, sperm whales, larger squid species, and great white sharks are all key predators who keep these daughters of the sea in check. Pods of dolphins will also harass a siren if caught alone. Additionally, they must fear other Medditerain sea monsters, such as the various species of sea serpent and most notably, the Leviathan. They are also kept out of deep water and the open ocean due to competition with merfolk. To escape predators, sirens will attempt to use their speed to escape, but if close enough they will come ashore or climb up intertidal rock outcroppings and wait their predator out. This comes with its own risks outside of suffocation, as on land, a siren is ill-equipped to defend herself against any land-based predators that may be patrolling the beach. Like wolves or large predatory felines.

In the wild, sirens can be found in the warm coastal waters of the Aegean, Ionian, and the Tyrrhenian Seas.   Because they depend on saltwater to survive, they, like many oceananic monsters, are contained in the Depths. The flooded lowest reaches of the Trench facility. They stay near the uppermost levels of the Depths in order to hunt.

In spite of their humanoid appearance, sirens are not blessed with great intelligence. Acting on instinct and mimicry rather than cleverness or strategy.

Like many other coastal fish species, sirens have a mutualistic relationship with the various species of cleaner shrimp and cleaning wrasse. These species are allowed to freely enter a siren’s mouth and gills. They feed on tiny bits of food stuck between the siren’s teeth and harmful parasites in its gums and gills. The siren gets a form of dental care and the cleaners get a free meal.

Based on historical accounts and interviews with credible supernatural sources, the history of the sirens has been pieced together. The sirens are the daughters of the primordial Greek sea god, Phorcyes. They were once a race of avian beings blessed with great intelligence regarding the art of song. Until they were tricked by the queen of Olympus into challenging, the goddesses of the arts, the Muses to a singing competition. The sirens lost and were cast from the skies and into the seas. For their hubris, their artistic minds were reduced to their base animalistic states only able to mimic the talents of voices not their own, and their once-feathered bodies warped into the scaly, piscine forms that we know today. In the 8th century, BCE, the sirens were encountered by the Greek hero, Odysseus, and his crew as they sailed home for Ithaca. At the time, it was believed that listening to a siren's song granted wisdom to the listener and having been forewarned of the creatures, he had all of his sailors plug their ears with beeswax and tie him to the mast. He ordered his men to leave him tied tightly to the mast, no matter how much he might beg. When he heard their beautiful song, he ordered the sailors to untie him but they bound him tighter. When they had passed out of earshot, Odysseus demonstrated with his frowns to be released. This event would be recorded by Homer in his epic poem.

The original sirens were all named by individual sources. Thelxinoe or Thelxiope, Thelxiepe, Thelxiep(e)ia, Aglaophonus, Aglaope, Aglaopheme, Aglaonoe, Molpe, Peisinoe or Pisinoe, Parthenope, Leucosia, Raidne, Teles, Ligeia, and Himerope.   Sadly due to the siren's current lack of intelligence and the species' vulnerability to predation, it is unknown if any of these original sirens are still alive today.

Despite their elusiveness, sirens have persisted in the imaginations of humans for centuries. Enough that the species’ name has entered the lexicon of several human languages. Sirens appear often in Greek and European art. Due to a lack of concrete sightings, they are often depicted differently from reality. Many early Greek scholars depicted sirens in their original avian form before their fall into the sea. In Christian art of the medieval era, sirens were regularly used as a symbol of the dangerous temptation embodied by women. It is here where they began to be depicted as mermaid-like creatures. Although slightly more accurate to modern-day sirens, the artists also adored the siren with more mammalian features such as a woman’s face, hair, and breasts.

Fishy Family

Despite the abundance of visual and behavioral similarities, sirens possess no genetic relation to the mammalian mermaids or ningen. But do have some relation to finfolk and Fog-Crawlers.