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Gameplay articles
Fallout 3Mirelurk
Mirelurk hunter
Mirelurk king
Point LookoutSwamplurk
Swamplurk queen
Fallout 4Mirelurk hatchling
Mirelurk spawn
Softshell mirelurk
Mirelurk razorclaw
Mirelurk killclaw
Glowing mirelurk
Mirelurk queen
Mirelurk hunter
Glowing mirelurk hunter
Albino mirelurk hunter
Mirelurk king
Mirelurk deep king
Glowing mirelurk king
Far HarborBloodrage mirelurk
Nuka-WorldNukalurk hunter
Nukalurk spawn
Nukalurk queen
Nukalurk king
Fallout 76Mirelurk
Softshell mirelurk
Mirelurk razorclaw
Mirelurk killclaw
Stoutshell mirelurk
Bloodrage mirelurk
Glowing mirelurk
Scorched mirelurk crab
Strangler mirelurk
Venomous mirelurk
Hardshell mirelurk
Mirelurk vorpalclaw
Steelshell mirelurk
Deadly mirelurk
Mirelurk hunter
Albino mirelurk hunter
Glowing mirelurk hunter
Grim mirelurk hunter
Relentless mirelurk hunter
Bloodthirsty mirelurk hunter
Deadly mirelurk hunter
Scorched mirelurk hunter
Mirelurk king
Mirelurk deep king
Savage mirelurk
Mirelurk high king
Glowing mirelurk king
Deadly mirelurk king
Scorched mirelurk king
Mirelurk queen
Glowing mirelurk queen
Scorched mirelurk queen
Strangler queen
Prime mirelurk queen Fallout 76 seasonal content
Mirelurk hatchling
Mirelurk spawn
Glowing mirelurk spawn
Scorched mirelurk spawn
Nuclear WinterMirelurk hunter
Fallout: The Roleplaying GameMirelurk
Mirelurk hatchling
Mirelurk hunter
Mirelurk queen
Fallout Shelter OnlineMirelurk
Mirelurk hunter

Mirelurk is a commonly used term referring to a range of mutated aquatic species endemic to the Eastern Seaboard, particularly the Capital Wasteland, the Commonwealth and Appalachia.

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

First introduced in Fallout 3, they have appeared in every Fallout game since, based on crustaceans or similar species, though not fish.


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 and General Atomics. Environmental organizations such as the Nahant Oceanological Society, dedicated to saving the oceans, attempted a variety of last-ditch efforts to raise awareness of this problem and encourage radical action to curtail environmental destruction at the hands of reckless corporations.[1] 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.[2]

Although the Great War ended 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 catalog it as simultaneously belonging to the Crustacea/Chelicerata subphylums, with the simultaneous classification of two distinct classes (Merostomata and Malacostraca). Both an Enclave researcher and the Lone Wanderer assigned it its own classification: Scylla serrata horrendus.[3][4] This groups mirelurks into the genus, Scylla (referring to a Greek sea monster), and the species, serrata (serrata being Latin for "forming a row of small sharp projections resembling the teeth of a saw"). The last part "horrendus," Latin for "dreadful" is the subspecies. The knowledge that mirelurks were much smaller before the bombs dropped and mutated them still persists among some wastelanders in the Commonwealth.[5] Mirelurks are also known to have a pronounced sensitivity towards white noise, as seen in Vault 92 and on Spectacle Island.

Although mirelurks tend to inhabit polluted rivers, coastal waters, and sewers, their meat is considered a delicacy among wastelanders, despite having the texture of vulcanized rubber.[6] Mirelurk hunters or herders can count on a steady demand for their meat and make a high profit selling it to wasteland traders.[7] 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).[8] They also grow remarkably fast, requiring just a few weeks for them to reach maturity. If corralled and domesticated, mirelurks can be a flexible supply of food. The Free States did, in fact, entertain such an option.[9]

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.[10] 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); if disturbed, the larval mirelurks within exhibit incredibly predacious behavior and are ready to attack if need be.[11]


The social structure of mirelurk species resembles a caste system, with intelligent mirelurk kings and the giant mirelurk queens at the top.[12]


FO76 creature mirelurk

Fallout 76

Gameplay articles: Fallout 3, Fallout 4, Fallout 76, Fallout: The Roleplaying Game, Fallout Shelter Online

One of the most common variants of the mirelurk, Scylla serrata horrendus (a name used by both the Enclave and the Lone Wanderer) is the result of mixing between horseshoe and blue crabs.[3][4]

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.[3][13][14]

Crab mirelurks instinctively know how to protect themselves with their shell. When faced with prey that can attack them at long range, a crab mirelurk will lower its head to cover its body with the chitinous shell, greatly increasing its ability to survive.[15] Other animals tend to avoid mirelurks, perhaps instinctively realizing the danger posed by the shell.[9]

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, abdominal claws strip the helpless prey as it is consumed down to the bone within minutes.[9]

Mirelurk hunter[]

FO4 Mirelurk hunter transparent
Gameplay articles: Fallout 4, Fallout 76, Fallout: The Roleplaying Game, Fallout Shelter Online

Hunters appear to be descended from lobsters rather than crabs, giving them an elongated appearance with a flared tail. Like their crab-like cousins, they also have powerful pincers and are even more aggressive. Their shells are typically more resilient, and they have developed the ability to spit an acidic substance at their prey.[16] The most characteristic elements of this kind of mirelurk are the oversized claws and its head, housing the eyes and antennae, its primary sensory organs.[Non-game 1]

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.[11]

Mirelurk king[]

Gameplay articles: Fallout 4, Fallout 76

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, and possess a defining "crowned and mantle" appearance. They also have the ability to cloak themselves in order to ambush unsuspecting prey.[17] They also uniquely possess both gills and lungs that were developed independently, allowing kings to survive on both land and water easily.[Non-game 2]

Mirelurk kings appear humanoid in shape, but have evolved from radiation and are distinctly non-sapien in their evolution. The upper and lower fins developed into jointed claws that can grab or slash, as well as flex 180 degrees. The evolutionary line of the mirelurk kings is completely separate from the crab-based mirelurks. Having developed independently, the intelligence of mirelurk kings is much higher than crab mirelurks and a symbiotic relationship formed from mirelurk kings where they developed an ability to control the less-intelligent mirelurks.[Non-game 3]

Snapping turtle variant[]

Mirelurk king

The reptilian mirelurk kings, standing upright on two feet, are the most human-like of the mirelurks.[Non-game 4] They have a symbiotic relationship with the other mirelurk types and commonly employ ranged attacks. 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. The swamplurk queen, found in Point Lookout, is highly adapted to its swampy environment. It is coated in a layer of algae which provides a degree of natural camouflage, and has the ability to spit corrosive, radioactive acid at its prey. Endemic to Lake Mead and the Colorado River is the lakelurk. They have a distinct, green coloration and the usual sonic attack.

Mirelurk queen[]

FO76 creature mirelurk queen

The mirelurk queen is a towering, heavily mutated, variant of the basic species. She is significantly taller than her standard counterparts and she maintains features from both mirelurks and hunters, such as the classic lobsteresque tail and the chitious shell on the top, to protect her from incoming damage. They are often spotted close to rivers, lakes or the seaside, where they lay their eggs, and are extremely territorial, aggressive, and protective their spawn; which they can also prematurely release from their abdomens to harass incoming threats in dire circumstances.

They are extremely resilient and can withstand prolonged damage to a great deal of their body, bar a few vulnerable areas. Their eight powerful legs allow them to push their weight forward, gaining speed before an attack, and heir claws have mutated into scythe-like arms. Furthermore, they also produce a highly corrosive acid that they can spray out with great velocity; this acid is capable of causing damage through all available armor types.

Mirelurk hatchling/spawn[]

FO4 Mirelurk Hatchling

Hatchlings are the collective term for mirelurk young. Mirelurks lay eggs, often in a well-protected nest. Occasionally when a nest is disturbed, eggs will hatch in response to the stimuli. Hatchlings are easy to dispatch by a competent individual providing the swarm isn't large. At this stage, their shells are soft, and they are around the size of a radroach.[18]

Behind the scenes[]

  • Adam Adamowicz created the mirelurks. For the king variant, he considered their opposable claws to allow them to employ weapons such as machine guns, though this was not implemented in the final design.[Non-game 5]
    • In his art, Adamowicz depicted a mirelurk king pulling a net ornamented with human skulls, and a lobster-like mirelurk rising from the ocean with a staff.
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


  1. Nahant Oceanological Society terminal entries; research terminal, Goals
  2. Nahant Oceanological Society terminal entries; research terminal, Lobster Growth
  3. 3.0 3.1 3.2 Enclave field research terminal entries, Enclave field research terminal, Field Entry: "Mirelurk"
  4. 4.0 4.1 The Lone Wanderer: "They descended from local crabs. I'd call them 'Scylla Serrata Horrendus.'"
    Moira Brown: "That's very scientific of you! Personally, I wasn't sure if they were crabs or if they came from some sort of brine shrimp, perhaps. Some of these observations about their armor and camouflage gave me an idea for reinforced, neutral-colored headgear. Here, consider it thanks for not interfering with them. Oh, speaking of which, take these. So you can continue to avoid them in the future."
    (Moira Brown's dialogue)
  5. John Hancock: "I'd heard Mirelurks were tiny before the bombs. Wonder what else might be plying those waters."
    (John Hancock's dialogue) Note: This line is spoken if Hancock is asked for his thoughts while on any large boat, such as the ones at Libertalia.
  6. Settler: "Fighting Mirelurks reminds me of fishing for salmon. Shame that their flesh has the texture of vulcanized rubber. Well, food is food."
    (Settlers' dialogue)
  7. Note for Ted
  8. Merc's orders
  9. 9.0 9.1 9.2 Mirelurk research
  10. Rivet City terminal entries; Bannon's terminal, Council Meeting Minutes
  11. 11.0 11.1 Behavior in Fallout 4.
  12. Ada: "It's fascinating that the Mirelurk's social order resembles a caste-like system."
    (Ada's dialogue)
  13. Fallout 4 loading screens: "Most Mirelurks are heavily armored and resistant to most forms of damage, but their faces are vulnerable."
  14. Tenpenny Tower terminal entries; exploration database, Mirelurks
  15. Behavior of mirelurks in Fallout 4 and Fallout 76.
  16. Fallout: The Roleplaying Game core rulebook, pg. 345
  17. Fallout 4 loading screens: "Some creatures, like the Mirelurk King, Chameleon Deathclaw and Sentry Bot, can utilize stealth to turn themselves almost invisible and ambush unwary prey."
  18. Fallout: The Roleplaying Game core rulebook, pg. 344
  19. Porter Gage: "Mudcrabs sure do have a certain... odor to 'em, don't they?"
    (Porter Gage's dialogue)


  1. The Art of Fallout 4 p. 196: "We really needed to include lobsters, given the location."
  2. Devastating-Dave: "That's really interesting to give him both lungs and gills. Is that to imply the mirelurk king, at least in part, mutated from lung fish?"
    Jonah Lobe: "I figured he might develop them independently, to be able to breathe in both land and water!"
    (Jonah Lobe Instagram on the Mirelurk King)
  3. Jonah Lobe on ArtStation: "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."
  4. The Art of Fallout 3 p. 42: "Snapping turtle variation"
  5. Fallout 3 concept art by Adam Adamowicz: "OPPOSABLE CLAW for gripping primitive weapon... like machine gun"
  6. Christiane Meister's portfolio on Zerply