Gameplay articles
Fallout 2Mantis
Fallout: New VegasGiant mantis
Giant mantis female
Giant mantis nymph
This is an overview article, focusing on background information and cross-game comparisons.

Mantises are mutated creatures found in the Southwest United States. They appear in Fallout, Fallout 2, and Fallout: New Vegas.


After the Great War, two different types of mantises can be found throughout the wastelands. The variant seen in California come from tandem exposure to radiation and Forced Evolutionary Virus[Non-game 1] while the other variant seen in the Mojave Wasteland are created by the horticultural experiments of Vault 22.[1]


Giant mantis

Giant mantis.png
Gameplay articles: Fallout, Fallout 2, Fallout: New Vegas

A giant version of the pre-War praying mantis. According to the G.E.C.K. they have the highest count of creatures in Fallout New Vegas.

Giant mantis female

Giant mantis.png
Gameplay article: Fallout: New Vegas

These female giant mantises are more powerful than male giant mantises, and larger too. They can be a source of mantis eggs.

Giant mantis nymph

Giant mantis nypmh.png
Gameplay article: Fallout: New Vegas

Young giant mantises who appear much smaller and weaker than adults. With a high enough strength, they can be killed simply by stepping on them.


Praying mantises are mentioned in the Pioneer Scouts entomologist exam.[2]


  1. Fallout Bible 0 Answer me these questions three:
    "2. Does FEV really cause sterility? In Fallout 1 it seemed like the answer was a resounding yes, and a number of reasons for this were given by Zax and Vree. But then in Fallout 2 after you take Marcus to the Cat's Paw he says "I hope she doesn't get pregnant" and says that the FEV doesn't make mutants go sterile, it just makes it take a few years "to get the juices flowing again". Moreoever, the deathclaws in Vault 13 were infected with FEV and yet they are able to reproduce. So, does the FEV cause sterility or not?"
    "FEV causes sterility in some creatures. FEV does cause sterility in super mutants and ghouls - Marcus' comment in New Reno was a joke only (and it was an inappropriate one, for which I apologize for). For other creatures, however, the FEV does not cause sterility - in fact, it may actually speed up their reproductive cycles (in tandem with potential drawbacks). Known species that can reproduce after being mutated with the FEV include most species of rats, the mantises (who are known to have bred so fast they cover the Salt Lake City area like blankets), the radscorpions, and the deathclaws. This is only a partial list."
    "3. Are the radscorpions a product of the FEV virus? When you talk to the doctor, Razlo, in Shady Sands, he tells you that they were once American Emperor Scorpions but that he has no idea how they mutated because radiation alone couldn't have done it. For that matter, what about all of the other creatures of the wasteland? Which ones have been mutated by FEV and which ones haven't? Maybe in the bestiary each creature could have a stat that shows it's level of FEV infection."
    "The radscorpions are a result of a combination of radiation and the FEV virus, and Razlo in Shady Sands is correct - they were originally Emperor Scorpions that have grown... big."
    "FEV-Infected Critters in the wasteland include almost all the ones you've seen in F1 and F2:"
    "Most species of rats."
    "Gecko lizards."
    "Various varieties of plants, including the Venus Flytrap."
    "Rumor has it some dogs were affected, but no one's seen any, so for now that's just rumor. Of course, the centaurs are a mash of human, dog, and various other parts... but hey, who knows how that mutation came about. Grey was probably messing around in one of his labs."
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