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This is an overview article which contains background information and cross-game comparisons. For game-specific information and stats, see the articles linked on the right.
Gameplay articles
Fallout 3Mirelurk
Mirelurk hunter
Mirelurk king
Point LookoutSwamplurk Gametitle-FO3 PL
Swamplurk queen Gametitle-FO3 PL
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 Gametitle-FO4 FH
Nuka-WorldNukalurk hunter Gametitle-FO4 NW
Nukalurk spawn Gametitle-FO4 NW
Nukalurk queen Gametitle-FO4 NW
Nukalurk Gametitle-FO4 NW
Nukalurk king Gametitle-FO4 NW
Fallout 76Mirelurk hatchling
Mirelurk spawn
Glowing mirelurk spawn
Scorched mirelurk spawn
Softshell mirelurk
Mirelurk razorclaw
Mirelurk killclaw
Glowing mirelurk
Bloodrage mirelurk
Diseased mirelurk
Scorched mirelurk crab
Strangler mirelurk
Mirelurk hunter
Albino mirelurk hunter
Glowing mirelurk hunter
Scorched mirelurk hunter
Mirelurk queen
Glowing mirelurk queen
Scorched mirelurk queen
Strangler mirelurk queen
Mirelurk king
Mirelurk deep king
Glowing mirelurk king
Scorched mirelurk king
Nuclear WinterPrime mirelurk queen Gametitle-FO76 NW
Venomous mirelurkGametitle-FO76 NW
Steelshell mirelurkGametitle-FO76 NW
Hardshell mirelurk Gametitle-FO76 NW
Mirelurk vorpalclaw Gametitle-FO76 NW
Deadly mirelurkGametitle-FO76 NW
Grim mirelurk hunterGametitle-FO76 NW
Relentless mirelurk hunterGametitle-FO76 NW
Bloodthirsty mirelurk hunterGametitle-FO76 NW
Deadly mirelurk hunter Gametitle-FO76 NW
Savage mirelurk kingGametitle-FO76 NW
Mirelurk high kingGametitle-FO76 NW
Deadly mirelurk king Gametitle-FO76 NW

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.


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.[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. 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.[3][4]

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.[5] 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).[6] 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.[7]

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.[8] 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.[9]


In Fallout 3, mirelurks are found in three variants: Mirelurks, mutated forms of Chesapeake Bay blue crabs (Callinectes sapidus); mirelurk hunters, mutated Atlantic Horseshoe crabs (Limulus polyphemus); and in the form of mirelurk kings, mutated snapping turtles. They can deal massive damage, and can absorb a great deal in return thanks to their shells. Generally, they can be found near sources of water, including the Potomac River in groups of two or more individuals of one of the above groupings.

In Fallout New Vegas, a strain of mutated turtles native to Lake Mead and other large water bodies appears; resembling the mirelurk kings of the Capital Wasteland, these humanoid turtles are called lakelurks by the locals.

In Fallout 4 and Fallout 76, mirelurks appear markedly more crab-like in appearance than those in Fallout 3, and their posture is generally crouched down to make their vulnerable faces harder to hit. Their shells also possess a mild reflective quality, as lasers ricochet off them. Mirelurk hunters are mutant lobsters rather than crabs. Mirelurk kings are less bipedal, have more prominent fins and have a long tail. Fallout 4 also adds the mirelurk queen, a gigantic creature slightly taller than a super mutant behemoth.



Gameplay articles: Fallout 3, Fallout 4, Fallout 76

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[10]) are quadrupedal and rounder.[11]

Their most noticeable feature is the large, chitinous shell that provides excellent resistance to firearms, melee weapons and even energy guns. Soft body parts, such as their faces and sections of their abdomen, are much less resistant.[3][12][13] 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.[14]

One 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.[15] Other animals tend to avoid mirelurks, perhaps instinctively realizing the danger posed by the shell.[16]

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.[16]

Softshell mirelurkEdit

FO4 Softshell Mirelurk
Gameplay article: Fallout 4

A weaker version of the mirelurk found in Fallout 4 and Fallout 76.

Mirelurk hatchlingEdit

FO4 Mirelurk Hatchling
Gameplay article: Fallout 4

Small, radroach-sized creatures that spawn from the eggs of a mirelurk clutch, or born live from the mirelurk queen. They appear to be baby mirelurks, and are instantly aggressive from birth.

Mirelurk hunterEdit

FO4 Mirelurk hunter transparent
Gameplay articles: Fallout 3, Fallout 4

A lobster-like creature that spits acid in splatter like shots.

Mirelurk kingEdit

Mirelurk king
Gameplay articles: Fallout 3, Fallout 4

Creatures that live symbiotically with other mirelurks, but according to Enclave research, appear to be mutated from snapping turtles. They use sonic attacks to kill their prey.


Gameplay article: Fallout: New Vegas

Mutated turtles native to the large water bodies of the Mojave Desert. They use sonic attacks to kill their prey.

Mirelurk queenEdit

FO4 Mirelurk queen transparent
Gameplay article: Fallout 4

Considerably larger and more dangerous than the other mirelurks. They have very large health pools, to the point they can even take several mini nukes to the torso without dying. One spawns at the Castle in Fallout 4 during the quest Taking Independence.


Gameplay articles: Fallout 3, Nuka-World

Can be found in the Nuka-Cola plant in Fallout 3. They are blue because of taking in the strontium isotope from the Nuka-Cola Quantum. Their meat gives 10 Action Points. Commonly found in amusement park Nuka-World in the Fallout 4 add-on Nuka-World.

Nukalurk queenEdit

Fo4NW Nukalurk queen at night
Gameplay article: Nuka-World

The Nukalurk queens can only be found in the Nuka-Cola bottling plant. She is a unique version of the mirelurk queen and has a blue glow due to the strontium isotope from Nuka-Cola Quantum. She has a large health pool, but when the Sole Survivor finally kills her, she drops queen Nukalurk meat which when consumed grants 120 Hit Points and 2 points in Endurance but 30 rads. The Sole Survivor can cook it at a cooking station to make a grilled version that has higher stats.


  1. Nahant Oceanological Society terminal entries: research terminal, goals: "Here at the Nahant Oceanological Society we strive to save our oceans by researching the longterm effects of radioactive exposure on aquatic life and working with the community to raise public awareness. We believe that companies such as Poseidon and General Atomics have gone unchecked too long and that radical action is neccessary to protect our world from a horrific future."
  2. Nahant Oceanological Society terminal entries: research terminal, lobster growth: "This is insane. An increase in average mass by 14% in crabs and 12% in lobsters is not something to be celebrated! If this trend continues, the additional food necessary to sustain the shellfish population could lead to colony collapse! I've tried again to bring our findings about the growth and mutations to the press and those assholes at GNN just took our findings and spun them into a story about how great shellfish season is going to be."
  3. 3.0 3.1 Enclave Field Research terminalentries, field entry: "Mirelurk": "Kingdom: Animalia
    Phylum: Arthropoda
    Subphylum: Crustacea/Chelicerata???
    Class: Merostomata / Malacostraca / ???
    Order: ???
    Family: ???
    Genus: ???
    After going to enormous lengths to procure DNA samples of hypothesized forebears, we cannot explain why ancestry evidence is present from two vastly different creatures; the Limulus polyphemus (horseshoe crab) and the Callinectes sapidus (blue crab). It's obvious that a mutation occurred, giving this creature bipedal movement and massive growth, but I cannot explain the presence of multiple subphylum markers in DNA/RNA. Given their mystifying origins, I have decided the species deserves its own classification, and have thus dubbed them "Scylla Serrata Horrendus." They can often be found in sewers and caves and should be considered hostile and very dangerous, as their chitnous shell provides excellent resistance to both firearms and hand-held weapons. They are disgusting creatures, and I cannot fathom their popularity as a food source among the citizens of the Wasteland."
  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."
  5. Note for Ted: "Ted,
    The Mirelurks busted out of the storage area and have been raisin' hell through the whole facility. Price says the bastards get smarter every day. He says I'm paranoid, but I think somebody might be sabotaging things around here. We've taken on so much extra help, I don't know who I can trust around here anymore. Things don't look too good.
    I don't think I'll be walking out of here, and I figure you should be the one to get our stash. I managed to get it hidden pretty well in case something like this happened.
    I don't want any of these damn fools tripping over it, so I threw a couple of curves in, but it's nothing you can't handle. Start with my terminal -- just log in and follow the instructions. And if for some reason you've forgotten the password, you might want to sit down and have a think with a Nuka-Cola, if you catch my drift.
    If this damn meat weren't in such high demand, I'd have pulled out of this racket before the word go. I got too greedy, Ted."
  6. Merc's orders: "By now, your handler's given you the location of the job and your basic orders. Here are the details.
    Traders have been making a killing with Mirelurk meat, and we've been losing business because of it. One of our people got involved with a caravan supplier, and we finally know where it's all been coming from.
    The meat's mostly coming from one group holed up along the river smack in the middle of the ruins. There's a huge old facility under some war memorial where they've herded up a nest of Mirelurks and have been breeding and butchering them. They've been in business for months and are sure to be sitting on a pile of caps. Take what you can carry -- we just want them out of the meat market. The rest is up to you.
    This isn't the biggest job, but pull it off clean and there's plenty more work for a man with your skills. Get back to your handler as soon as the job is done and we'll be in touch."
  7. Mirelurk research
  8. Rivet City terminal entries, Council Meeting Minutes: "In attendance:
    Science Rep. - Dr. Madison Li
    Civilian Rep. - Bannon
    Security Rep. - Harkness
    * Bridge repair continues to be a drain on funds. Permanent bridge considered, but dismissed as too risky, in case of attack.
    * "Bridge Tax" for non-residents proposed by Bannon. Vote fails.
    * Hydroponics and city health continues well, thanks to the efforts of Dr. Li and her scientific team. However, system breakdowns are commonplace, requiring much maintenance.
    * Li proposed recruiting other scientific minds from Tenpenny Tower or Underworld. Vote fails.
    * Attempts to clear out the Mirelurk infestation in down-below continue as usual. Harkness and team is able to contain them and occasionally wipe them out, but they continue to nest in the area, posing a theoretical risk if they ever turn aggressive towards higher decks.
    * Bannon suggests closing off lower deck fore. Vote fails.
    * Funds and ammunition allocation for a Mirelurk cleaning operation proposed by Harkness. Vote passes.
    * Dr. Li leaves early to oversee hydroponics testing.
    * Meeting adjourned."
  9. Behavior in Fallout 4.
  10. Quercus: " Oh, lovely! The classic mirelurk, migrated all the way from the Chesapeake Bay. Your friends have taken up quite a residence here, haven't they?"
  11. Morphological differences between the two crab mirelurks.
  12. Fallout 4 loading screen hints: "Most Mirelurks are heavily armored and resistant to most forms of damage, but their faces are vulnerable."
  13. Tenpenny Tower terminal entries; exploration database, mirelurks
  14. Softshell mirelurks
  15. Behavior of mirelurks in Fallout 4.
  16. 16.0 16.1 Mirelurk research
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