Mirelurk

Mirelurk is a commonly used term referring to a range of mutated crustacean and turtle species endemic to the Eastern Seaboard, particularly areas belonging to the Columbia and New England Commonwealths.

A similar term, lakelurk, is used to refer to mutated turtles in the Colorado watershed in the Mojave Wasteland.

Background
Mirelurks have the dubious distinction of being one of the first radioactive mutants to emerge into the world, as a result of widespread radioactive pollution of the environment by United States megacorporations such as Poseidon Energy or General Atomics. Environmental organizations such as Nahant Oceanological Society, dedicated to saving the oceans, attempted a variety of last ditch efforts to raise awareness of the problem and encourage radical action to curtail environmental destruction at the hands of reckless corporations. However, their efforts were in vain. Ignored by authorities, to the point where they refused to even take their phone calls (as was the case with the Boston Port Authority), they attempted to garner attention by reporting the situation to the Galaxy News Network. The media ignored their reports as well, except for running a story about the upcoming shellfish season and how great it was going to be. Of course, it neglected to mention that the average increase in mass on the order of 14% in crabs and 12% in lobsters meant that the available food supply would run out quickly, leading to colony collapse and localized extinction.

Although the Great War put an end to corporate pollution, it was replaced by overwhelming amounts of nuclear fallout instead. In the ensuing melting pot of mutations the modern mirelurks emerged. Attempts to classify the resulting creatures have proven difficult. The crab mirelurk, for example, contains multiple phylum markers from two distinct and unrelated species: The Atlantic horseshoe crab (Limulus polyphemus) and the Atlantic blue crab (Callinectes sapidus). As such, it would be necessary to catalogue it simultaneously as belonging to the Crustacea and the Chelicerate phylums, with simultaneous classification a two distinct classes (Merostomata and Malacostrata). As such, wasteland scholars generally assign it its own classification: Scylla serrata horrendus.

Although mirelurks tend to inhabit polluted rivers, coastal waters, and sewers, their meat is considered a delicacy among wastelanders. Mirelurk hunters and herders can count on a steady demand for their meat and make a high profit selling it to wasteland traders. However, the size of the meat market means competition is stiff and suppliers can be targeted by rivals attempting to knock them out of the market (sometimes literally). They also grow remarkably fast, requiring just a few weeks for them to reach maturity. If corraled and domesticated, mirelurks can be a flexible supply of food. The Free States did, in fact, entertain such an option.

Mirelurks can also be a blight on permanent settlements, as is the case with Rivet City. Mirelurks nesting below inhabited decks are a continued nuisance for denizens of the city, despite regular extermination operations by the city's security team. Infestations are made even worse by the fact that mirelurks have adapted to lay their eggs in multiple small nests throughout shallow water (unlike pre-War crustaceans that adhered their eggs to their body), likely because they grow larger relative to the parent and have developed a hard calcified shell; if disturbed, the larval mirelurks within exhibit incredible precocious behavior and are ready to attack if need be. 

Crab mirelurk (Regular)
 One of the most common variants of the mirelurk, Scylla serrata horrendus is the result of mixing between Chesapeake Bay horseshoe and blue crabs. Regional variations exist: for example, crab mirelurks in the Capital Wasteland tend to be bipedal and slimmer, while those in the Commonwealth and Appalachia - migrating from Chesapeake Bay - are quadrupedal and rounder.

Their most noticeable feature is the large, chitinous shell that provides excellent resistance to firearms, melee weapons, and even ray guns. Soft body parts, such as their faces and sections of their abdomen, are much less resistant. Of course, that only applies to adult mirelurks. The shell's chitin takes time to harden and young mirelurks are quite vulnerable at that stage of their life.

An interesting feature of crab mirelurks is that they instinctively know how to protect themselves with their shell. When faced with prey that can attack them at range, a crab mirelurk will lower its head to cover its body with the chitinous shell, greatly increasing its ability to survive. Other animals tend to avoid mirelurks, perhaps instinctively realizing the danger posed by the shell.

When hunting, mirelurks rely on their extraordinary sense of smell, with their poor eyesight a secondary aid. They catch their prey with their primary large claws. Once immobilized, the prey is then stripped down and consumed with the claws on their abdomen, capable of stripping animals down to the bone within minutes. 

Lobster mirelurk (Hunter)


The lobster mirelurk is an unique mutation found in New England environs, called mirelurk hunter by its denizens. The most characteristic elements of this kind of mirelurk are the oversized claws and its head, housing the eyes and antennae, its primary sensor organs. Although they lack the protection of their crab cousins, lobster mirelurks make up for it with their more powerful melee strikes and the ability to spit corrosive acid at targets. Its prey is usually consumed whole and digested in the stomach, using acids and teeth embedded in the lining. 

Turtle mirelurk (King)
The third of the major mirelurk types, the kings are heavily mutated snapping turtles. Standing upright on two feet, they are the most human-like of the mirelurks, especially in terms of behavior. They have a symbiotic relationship with the other mirelurk types and commonly employ ranged attacks which the other variants lack. Their hands allow them to employ simple tools. They also constantly exude slime to prevent their skin from drying.

Though it appears human in shape, the Mirelurk King evolved in non-sapien ways, forced by the pollution and radiation. Its upper and lower fins have developed joints and claws capable of flexion. Although there is no evolutionary link between the mirelurk kings and the mirelurks themselves, the species have formed a symbiotic bond of sorts: The kings' superior intelligence allows them to dominate and perhaps control their less intelligent mirelurk peers, which in turn can expand their territory more efficiently under their control. 

Common king


The mirelurk king lacks the characteristic shell of other mirelurk variants, but makes up for it with their thick, leathery skin, powerful arms and legs, and the ability to shriek at their attackers. This sonic attack is particularly dangerous against unaware or weakened targets.

Commonwealth mirelurk kings have distinct adaptations to its water-rich environment, with pronounced webbed extremities and numerous fins all over its body. Their coloration is also red, rather than the typical blue. They also have the ability to cloak themselves in order to ambush unsuspecting prey.

Swamplurk queen


A regional variation of the mirelurk king, the queen is found in Point Lookout. The environment of the swamps resulted in adaptations such as a coat of algae covering its skin, providing a degree of natural camouflage, and the ability to spit corrosive, radioactive acid at its prey.

Lakelurk
A unique type of turtle mirelurk, endemic to Lake Mead and the Colorado River. They have a distinct, green coloration and the usual sonic attack.

Behind the scenes
"The mirelurks got a bit of a reboot visually, as well as significant expansion on the variants with the addition of the hunter and the queen. This was simply a case of wanting to try something a bit more animalistic and to move away from the guy-in-a-suit vibe of the original."

- The Art of Fallout 4

"Though it appears human in shape, the Mirelurk King evolved in non-sapien ways; namely, its upper and lower fins have developed joints and claws capable of flexion. Similarly, there is no evolutionary link between the Mirelurk Kings and the Mirelurks themselves; the story I told myself while building this Lovecraftian monstrosity was that his kind had evolved in ways that allowed them to dominate and perhaps control their less intelligent Mirelurk peers.

To reinforce this idea, I doubled down on the “Kingly” imagery by sculpting a hard-shelled crown (which was in the concept art to begin with) a la Dunkleosteus, as well as dressing him in long, sweeping red “gill robes,” like the ancient western kings (which was not in the concept art). I built him anticipating that he’d walk upright, proudly, with this chest out - like the Fallout 3 variety. Alas, the animator chose a more froggish route.

The model itself is 9.1K triangles, the textures 2048. It was created for Fallout 4."

- Jonah Lobe 