“My boys are huntin' 'Lurks. Finest meat you can get, and it don't move around in your stomach like Mole Rat does. Right dangerous, those things. Just as soon take your head off as look at'cha. Watch yourself out here. They're all over.”— Sparkle, Fallout 3
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 long 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.
“Mirelurks are naturally armored throughout their body... with the exception of the face. Try using V.A.T.S. to target this area, and kill them before they get close enough to attack.”— Fallout 3 loading screen
All mirelurks, except for kings, are protected by a thick shell that is difficult to penetrate, even with powerful ballistic weapons such as the Gauss rifle. The face, however, is unarmored but presents a small target. Furthermore, when charging, a mirelurk will lower its head to protect this area. However, the face will inevitably be exposed once the creature commences close combat. Extremities are also more vulnerable than the rest of the body, though not as much as the face. Low-level characters will find mirelurks to be among their deadliest enemies.
Mirelurks are extremely territorial, and they will attack any trespasser on sight and run it down relentlessly. They also take advantage of their strength in numbers, often breaking away to solicit support if there are additional mirelurks in the area. Mirelurks are never found alone.
Mirelurk meat, especially the soft shell variety, is highly nutritious and grants some of the highest HP replenishment of any food in the game. This is reinforced by Grandma Sparkle, as she will tell the player character that mirelurk meat is "the best meat you can get out here." Both are slightly radioactive, but no more than typical food. Chefs throughout the wasteland have developed many culinary uses for mirelurk, the most prominent being the creation of mirelurk cakes. A recipe for these cakes can be found in a fridge in the Anchorage War Memorial, but it cannot be made by the player character.
The most common type of mirelurk has a whitish-gray shell, is about a head shorter than a normal human, and walks slightly slower. Mirelurks fight with their claws and lack ranged attacks. At close range they can charge forward in a brief burst of speed for a headbutt, which also makes it impossible to target their face. However, their face is most vulnerable in the seconds after a headbutt, when their 'head' is raised.
A much larger, greenish-brown colored version of mirelurk. In addition to their two main arms, hunters also have two pairs of small, segmented appendages growing out of their chest which they may attack with, but do so rarely. Mirelurk hunters inhabit the Potomac River in the northern wastes and several sewers and caves near the metropolitan area of the capital, along with a good number in the Anchorage War Memorial. Hunters are very aggressive and are more difficult to kill, due to their increased strength, speed, and health. They appear more frequently at higher levels. Their powerful pincers inflict heavy damage, and can knock back low level characters with ease.
Mirelurk kings do not particularly resemble their crab-like "subjects," being more humanoid in appearance, unable to float in water, and with heads not unlike those of snapping turtles. The only commonality appears to be their arms, ending in pincers.
Also, unlike the other mirelurks, they have a ranged sonic projectile attack that bypasses Damage Resistance and is particularly effective at crippling the target's head. Mirelurk kings have less damage resistance than the "lower orders" of mirelurk but require more damage to kill. They can be pickpocketed, though they don't have anything in their inventory, and reverse pickpocketing a grenade or mine reduces Karma. Mirelurk kings appear more frequently as the Lone Wanderer reaches higher levels.
This mirelurk hunter variation is indigenous to the Nuka-Cola plant. They are uniquely colored, possessing a dark blue exoskeleton stippled with glowing blue features along certain regions of their bodies. This coloration is likely due to prolonged exposure and/or consumption of the radioactive strontium isotope that was used to color Nuka-Cola Quantum before the Great War. Nukalurks appear in both "regular" and "hunter" versions similar to their mirelurk cousins, yet the difference is purely aesthetic.
Their meat is notable for a small boost in AP (a reflection of the effects of Nuka-Cola Quantum), in addition to radiation and Hit Points. However, only ten nukalurks appear in the game, limiting the amount of meat available to no more than ten as they do not respawn.
Swamplurks (designated "mirelurk" in-game) are a variation of mirelurk that inhabit the swamps of Point Lookout. They are visually identical to mirelurk hunters except for their size, green-tinged shells (due to the swampy environment) and the lack of vestigial limbs on their abdomen.
Swamplurk queens (simply called "swamplurk" in-game) are a variation of the Capital Wasteland's mirelurk kings that inhabit the swamps of Point Lookout. Like the mirelurk kings, they are mutated from snapping turtles native to local rivers. They look extremely similar to kings, distinguishing traits being a mossy coloration and strangely shimmering, glowing, yellow eyes.
Unlike mirelurk kings, the swamplurk queen spits acid from its mouth, similar to a centaur. Although not radioactive, this acid inflicts high damage. Even with its lack of clothing, the swamplurk queen can be reverse pickpocketed with explosives. However, this results in negative Karma.
Despite their aquatic origins, mirelurks cannot attack while swimming. A king's sonic attack, however, will penetrate water, so a swimming player character is not safe from this variety.
Mirelurks make a loud, distinctive clicking noise, which will easily give away their presence.
Mirelurks appear to be immune to "stopping power" short of a mini nuke. Even a missile or Gauss rifle bolt to the face will not faze them or slow their charge. Power fists and deathclaw gauntlets appear to repel them to some extent, but this is more likely due to their attack animations which tend to "push" things away.
A Brotherhood initiate can be found burning a dead mirelurk with a flamer near the Jefferson Memorial after Project Purity becomes operational. He remarks that the creatures are dying in the new pure water and appear to require contaminated water to live. (He also notes that they smell rather bad.) There is also a Brotherhood Knight patrolling the steel deck, who mentions that they are encouraged to take potshots at the dying mirelurks.
Despite this, the mirelurks that re-spawn in the tidal basin do not actually die by swimming in the water, though they spawn with greatly diminished health, allowing the Brotherhood or the player character to easily kill them. Over time, however, they wear down the Brotherhood members who fight them and kill them or cause crippling injuries.
It appears that a re-skinned mirelurk king is later used in Fallout: New Vegas, where it is given the name lakelurk. It is unknown whether or not they are of the same species.
Although Nukalurks are filled with the isotope for Nuka-Cola Quantum, they oddly don't inflict radiation damage on their victims.
A mire is an area of bog, marsh, or other wet, swampy ground. As such, the mirelurks' name is fitting, as they tend to lurk in mires.
The mirelurks were created and modeled by Jonah Lobe, who was inspired by old rubber-costumed monsters from 1950s pulp films. However, he has stated that he was not satisfied with the final result and greatly prefers the mirelurks of Fallout 4, which he also modeled.
The following is based on Fallout 3 cut content and has not been confirmed by canon sources.
Early in the development of Fallout 3, when undetected, mirelurks would crouch down and fold their limbs under their shell to avoid view, giving the outward appearance of a rock (much like the mudcrabs of Bethesda'sElder Scrolls series). When anything came closer, they would slowly stand up.
End of information based on Fallout 3 cut content.
PCPlaystation 3Xbox 360 Mirelurks killed in water will often flip over on their fronts and twitch. This is purely a graphical glitch related to their wireframe. Sometimes they will twitch so much they fall right through the floor, or become trapped in walls and doors while constantly playing a collision noise that can alert other enemies. [verified]
PCPlaystation 3 Sometimes when mirelurks are killed on land, body parts will sink into the textures on the floor, as much as half their body, and the remaining parts will flail and bounce. [verified]