Fallout Wiki
Fallout Wiki
Gameplay articles
Fallout 3Mirelurk
Mirelurk hunter
Mirelurk king
Point LookoutSwamplurk
Swamplurk queenre
Fallout 4Mirelurk hatchling
Mirelurk spawn
Softshell mirelurk
Mirelurk razorclaw
Mirelurk killclaw
Glowing mirelurk
Mirelurk queen
Mirelurk hunter
Mirelurk king
Far HarborBloodrage mirelurk
Nuka-WorldNukalurk hunter
Nukalurk spawn
Nukalurk queen
Nukalurk king
Fallout 76Mirelurk
Mirelurk hunter
Mirelurk king
Mirelurk queen
Mirelurk spawn

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.


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 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 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. Wasteland scholars generally assign it its own classification: Scylla serrata horrendus.[3][4] 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. Mirelurk hunters or herders can count on a steady demand for their meat and make a high profit selling it to wasteland traders.[6] 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).[7] 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.[8]

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.[9] 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 incredible predacious behavior and are ready to attack if need be.[10]


Crab mirelurk

Fallout 76

Gameplay articles: Fallout 3, Fallout 4, Fallout 76

Mirelurks are heavily armored and resistant to most forms of damage, but their faces are vulnerable.[3][11][12] Other animals tend to avoid mirelurks, perhaps instinctively realizing the danger posed by the shell.[8]

Mirelurk king

Gameplay articles: Fallout 4, Fallout 76

Mirelurk kings have distinct adaptations to their water-rich environment, with pronounced webbed extremities and numerous fins all over its body. They also have the ability to cloak themselves in order to ambush unsuspecting prey.[13]

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
  • Porter Gage refers to mirelurks as "mudcrabs" when talking to him.[14] Mudcrabs are crab-like creatures in The Elder Scrolls series.
  • Jonah Lobe stated that their design of mirelurk king feature both lungs and gills.[Non-canon 1]


  1. Nahant Oceanological Society terminal entries; research terminal, Goals
  2. Nahant Oceanological Society terminal entries; research terminal, Lobster growth
  3. 3.0 3.1 Enclave field research terminal entries, Enclave field research terminal, Field Entry: "Mirelurk"
  4. 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. Note for Ted
  7. Merc's orders
  8. 8.0 8.1 Mirelurk research
  9. Rivet City terminal entries; Bannon's terminal, Council Meeting Minutes
  10. Behavior in Fallout 4.
  11. Fallout 4 loading screens: "Most Mirelurks are heavily armored and resistant to most forms of damage, but their faces are vulnerable."
  12. Tenpenny Tower terminal entries; exploration database, Mirelurks
  13. 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."
  14. Porter Gage: "Mudcrabs sure do have a certain... odor to 'em, don't they?"
    (Porter Gage's dialogue)


  1. 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