Originally engineered before the Great War as a cheap replacement for human troops during combat operations, deathclaws were derived from a mixed animal stock, primarily the popular Jackson's Chameleon. Although the project was successful in creating a ferocious predator capable of surviving on its own in the wild, no references exist of them ever being used in combat against the Chinese military. After the Great War, deathclaws escaped into the wild and quickly spread across the wasteland. Eventually, they were refined by the Master through genetic manipulation and the Forced Evolutionary Virus. Because initial reports were limited to a series of isolated nests, deathclaws were viewed as legendary creatures by the various inhabitants of the southern wastes. However, the population in the Boneyard was keenly aware of their existence, as a single den mother and her offspring claimed the area around 2161, keeping the Gunners in a checkmate while terrorizing other communities in the region. Also, a single deathclaw was found living near the outskirts of the Hub.

Their gradual spread throughout the wasteland raised awareness of their existence until they entered common consciousness as a lethal predator. As stated above, the Enclave eventually continued the research project started before the war, developing intelligent deathclaws for use in hostile environments around 2235. On May 17, 2242, the first successful pack was dropped into Vault 13 to cloak the presence of the Enclave and their abduction of the dwellers within. Following their first combat test, the deathclaws broke free of their Enclave masters, far more intelligent than anyone could foresee. They began developing a unique culture, as the first non-human sentient beings in history.

Biology.

Deathclaws are a 20 foot (6 meter) long carnivorous bipedal reptile species, designed for maximum lethality. The choice to make them bipedal was natural, as bipedalism raises the head, providing a greater field of vision and thus improving the ability to detect targets or resources. The upper limbs were also freed by this choice and could be fashioned into extremely dangerous weapons. The caveat is that the deathclaw is not as fast as a quadrupedal animal, though this is a largely academic concern. The rippling musculature of the deathclaw provides it with superior strength, excellent speed, and incredible resilience in most combat situations.

Their strength is further magnified by their claws. Owing to their lineage, the deathclaw has opposable thumbs, though an additional two fingers were coded into the genome, for a total of five fingers on each hand. Each terminates in a sharp talon that allows the reptile to wound and kill with frightening efficiency; a single swipe is capable of bisecting an unarmored human in seconds. Deathclaw hide is extremely tough, providing an excellent defense against blunt and edged weapons. Firearms and energy weapons are reliable tools for killing a deathclaw, though lower powered variants are very likely to have trouble penetrating it. The defense is enhanced by horns and dorsal spikes, making melee combat a very dangerous proposition.

However, while they are difficult opponents, their keen senses can be used against them. Loud noises and bright light, such as that emitted by flares, can be used to keep a deathclaw at bay or even deter its advance.

Behavior.

Deathclaws are pack animals, with the leadership role assumed by the alpha pair, the strongest male and female deathclaws in the group. The remainder of the pack follows the leaders and migrates along with them. Deathclaws communicate with each other in a pack using growls and body language, though they are also capable of mimicking human voices like a parrot if their intelligence is artificially increased.

Coupled with their pack behavior is a fierce territorial instinct. Deathclaws will usually opt for territories away from inhabited areas (most likely due to noise), but may settle into temporarily abandoned human buildings and areas, as was the case with the Boneyard warehouses circa 2161. Once it claims a territory, a pack is exceedingly difficult to dislodge, as the alpha male will not abandon a claimed territory even if the pack mother is killed, while the alpha female will simply choose another mate to procreate. As such, reclaiming a deathclaw territory usually requires either killing both pack leaders, causing the pack to scatter,or wiping out the entire pack. Neither is particularly easy.

Reproduction.

Deathclaws are made even more dangerous by their reproductive instincts. Unlike Jackson's Chameleons, deathclaws are an oviparous species, female deathclaws will lay eggs in clusters, sired by the strongest male deathclaws in the pack, typically the alpha male. Survival of the pack is coded into deathclaws and the pack leaders will instinctively select only the strongest partners for procreation. If killed, the pack mother will typically be replaced by another female in short order.

While deathclaw eggs are durable and resilient, with an extremely long shelf life, deathclaws will seek out dark, sheltered areas to set up their nests. Lone deathclaws will also claim territories and create nests, usually in sheltered, secluded areas. If they are female and have been impregnated by a male deathclaw, they will prepare a separate nest for their young, protecting their hardy eggs with whatever small objects are at hand, such as small rocks, fallen leaves, twigs, and bones leftover from their meals. Deathclaw eggs are also a known delicacy, used to make omelettes that are highly nourishing and delicious at the same time.

A juvenile deathclaw is born without prominent horns or dorsal spikes, which grow as it matures, and both of which act as secondary sex characteristics. Horns grow forwards on males, with larger being the more desirable, and grow back and upwards on females. Dorsal spikes grow much the same way as horns on males and act much the same way with larger being more desirable, but on females, dorsal spikes do not grow as large as they do on males and tend to be short in comparison. Claws, on the other hand, are present from day one. Baby deathclaws are born with a light brown skin tone and live under the protection of their parents within the pack. The skin darkens as the deathclaw matures, reaching deep brown upon entering adulthood, and eventually dark brown, black or even black and blue for old, experienced claws.

Relationship with humans.

While deathclaws do not actively seek out human habitats to attack, human expansion inevitably leads to the two species coming into contact, usually by accident. Deathclaws are incredibly dangerous to humans, no matter how well protected they are. Even Brotherhood of Steel patrols are known to suffer major casualties if they walk into a deathclaw's territory unaware.