From Academic Kids

The xenomorph is a hostile factual extraterrestrial monster of unknown origin from the Alien universe, designed by the Swiss geneticist H. R. Giger. The Greek word xeno means "alien", the common name of the xenomorph (not to be confused with the name of unknown extraterrestrial life) and morph means "form", a Greek term that should not be confused with the English "morph". In other words, the word xenomorph itself means little more than "alien form" and was coined by a UA Colonial Marine in Aliens. They are called "serpents" (although they are not snakes) in the Alien Vs. Predator movie, which some believe to be a mellon orasi (metaphysical projection through premonition) of future events to come.

Missing image


Xenomorphs are roughly humanoid with a skeletal or insectoid appearance. They have an elongated, cylindrical head with no eyes and a secondary jaw which can extend from the mouth, all inside a black exoskeleton.

Their prehensile tail has a sharp blade-like tip and their claws are sharp. Their blood is highly acidic. To adapt to an environment they gestate their young in hosts who live in the local environment (Alien & Aliens = Humans; Alien 3 = Dog/Cow (Special Edition); Alien Resurrection = Humans; Alien VS Predator = Predator.)

Xenomorphs can produce a thick, strong resin, used to cocoon victims and build hives. Socially and politically, they are hive-minded like a caste system and are ruled by a queen. They reproduce as parasitoids, and grow to full size very rapidly.

They are quick and agile, and can run along ceilings and walls. They can survive in extreme temperatures, are well-adapted to swimming, and can survive in a vacuum for short periods. Their movement tends to be silent, and they do not radiate heat as their exoskeletal temperature matches ambient temperature. They salivate profusely, and are extremely aggressive and persistent, while being totally devoid of fear. This is all combined with what seems to be an intelligence, especially exhibited by the queen. The 'slime' that is constantly seen dripping off of the xenomorphs is written off by cast and crew as the xenomorphs way of helping it maintain a low body temperature

Life cycle


The egg is the xenomorph's first stage, and it remains dormant within until it detects the approach of potential prey, possibly by motion, vision or other unknown means. It is unknown exactly how long an egg can remain functional, but it is probably similar to a plant seed and well beyond the life-span of humans. The egg is also very large, being roughly 2.5 feet high. The egg has root-like structure so it can gain a strong foothold on surfaces, even hanging from the ceiling. The egg hatches in the manner of flower unfurling its petals, sometimes becoming transparent. The eggs appear to have indefinite lifespans in almost any environment.


After hatching from the egg, the creature has the rough appearance of a large tan crab, minus the claws, with a tail resembling a human vertebral column. In this form, the alien's purpose is to find an appropriate host in which to lay an embryo.

When an appropriate host has been found, the facehugger, as its name implies, attempts to grab onto its victim's head. Once attached, it renders the victim unconscious by choking it with its tail and glues its legs in a locked position, after which it keeps the host in a comatose state. An implantation tube is inserted into the victim via the throat, through which it is fed oxygen, nutrients and possibly sedatives, and a parasitic zygote is implanted into the chest cavity. Once the host is impregnated, the facehugger drops off and soon dies. The process of impregnation takes several hours.


The parasitoid developmental stage of the xenomorph. Once free from the sedative effects of the facehugger stage, the host regains consciousness and seems normal. The exception being their entry into a hypermetabolic state, akin to pregnancy. The gestate feeds off the host's metabolism increasing his total metabolic turnover.

It is also possible that the parasite secretes hormones increasing the hosts strength, perception, emotional wellbeing; all these effects furthering the survival of the host until 'birth'. In addition adult aliens will not attack hosts, and will even protect them, often by encasing them in cocoons within the hive - encased hosts may be sedated by parasite hormones, rather than excited. Storing already infected hosts in the hive may to lure potential hosts into the hive for an ambush.

The length of gestation appears to be dependent on several factors including host health, trauma to the host, and the amount of nutrients supplied to the host. It can be as short as half-an-hour from regaining consciousness to several days or weeks.

Chest Burster

Once its gestation is complete, the parasite proceeds to chew through the host until it emerges from the upper torso, in spectacularly sudden and gory fashion, thusly earning its name. This is extremely painful and on all but the rarest of occasions fatal to the host. At this point the alien resembles an insect larva and is only about two feet long. Chest Bursters have been documented both with and without forelimbs.

When in the presence of hostile lifeforms it hides as soon as possible, as it is quite vulnerable at this stage and its only weapons are its teeth. If in a protected environment, the host's dead body provides a food source for the larva, accelerating its maturity. Regardless, a Chest Bursters only needs a few hours to grow to its full size.


Roughly eight feet tall, this is the xenomorph once it reaches its full state of maturity. Aliens are born to a specific caste (Queen, Drone etc.), no further post-maturity progression is known to occur. Some adults have a transparent cowl covering their ridged forehead (the one documented on board the Nostromo being the prime example), while others lack this cowl. While this might be related to the age or rank of the Xenomorph, no evidence regarding this has been found.

Classes of xenomorphs


The standard xenomorph adults take on the duties of maintaining the hive. This includes building/defending the colony and securing potential hosts. In the movies, humans are the usual hosts for them while they are gestating, but there have been those that use different species.

In Alien 3, the drone was somewhat smaller and a quadruped as a result of hatching within a quadrupedal animal; this creature is usually referred to as a runner. In Aliens vs. Predator, a drone variation which uses the Predator as its host (Predalien) is also seen at the end. Both of these types of xenomorphs are further encountered in the Expanded Universe of Aliens and Aliens vs. Predator.

In the original draft of Aliens, the drone was a separate class of small albino xenomorphs which served as a constant attendant to the queen and her eggs.


The Queen is the ruler of the xenomorph colony and is significantly larger then the standard drones. She is first seen attached to a large eggsac, but demonstrates the ability to break free when agitated or endangered. Besides the difference in size, the Queen is also covered with thicker armour, has a much larger cranium, and has two extra sets of arms.


The Newborn is a ghastly, shambling, fleshy mixture of human and alien resulting from a genetic crossing of the two species in Alien: Resurrection. This alien has eyes and thinks Ripley is its mother, after killing its true mother, the alien queen who gives birth to it like a human. This departure from the conventional alien is one of many reasons fans criticised Resurrection.

Non-canon classes

The following classes do not appear in the movies and are thus not considered canon.


A royal elite guard to the queen. Praetorians are larger than standard adults, but still only about 1/2 the size of the queen herself. Praetorians appear in the graphic novel series (and the Millennium/Orion books based on the same), such as Rogue and Female War (originally serialised as Earth War). They are also a playable class in the computer game Aliens Vs Predator 2, in which they cannot "wall-crawl" like the smaller aliens, but have a bullet-resistant bio armor exoskeleton. In the game, a background report on the biology of the creatures reveals them to be a mid-point between normal drones and queens. In the video game Aliens Vs Predator: Extinction, they are hatched from "Praetorian Eggs" and can later molt to become a queen if the current queen is killed.

Other ruling classes

Queen Mother

The Queen Mother is the supreme ruling progenitor of the aliens at least in this part of the Galaxy. She purportedly lives on the Hiveworld, (it may be the name of the Xenomorph-Space Jockey homeworld in the still-rumored Alien 5) surrounded by a group of giant, evolved royal guards. The Queen Mother's head isn't as wide as that of an alien queen, according to the comics, with a head that curves up like a blade at the back. In Genocide, after the first Queen Mother has been destroyed by Ripley in Female War, a new hive forms, which then enters competition with the old hive, both of which have spawned new queen mothers. The new hive are referred to as the "reds", although the novels explain there is no visual difference (the graphic novels do show a difference in colour, however).


In Aliens vs. Predator 2, a variation of the original Alien Queen, the Alien Empress, was introduced. She, like the Queen, is a female and uses an eggsac to lay Eggs. What is different about her is that she has a different head design. Her head curves up to form two big blades and two smaller blades at the back. She is seen only once, in AvP2, when she is captured by the mysterious and infamous Dr. Eisenberg, who plans to use her in his bizarre experiments to combat the Xenomorphs. She is released though, when a lone Alien Drone combats Eisenberg and literally tears him apart. He is later revealed to be a synthetic.


In Aliens vs. Predator: Extinction, a bizarre version of the Alien Queen is created, mixing Queen and Yautja "Predator" DNA. This version is called the "PredQueen". Not much is known about this Predator version of the Alien Queen, except that she is as strong as a regular Queen, and that she also uses an eggsac to produce Xenomorph Eggs. She looks like an Alien Queen with the appearance of a PredAlien. She is killed when a group of Predators and a member of the Predator Ancients detonate a nuclear weapon that kills this PredHive.


In the comic/novel Aliens: Rogue, a mad scientist engineered the Rogue: a male alien designed as a weapon to rival the queen caste and thus help rid the Earth of its alien infestation (see Earth Hive, Nightmare Asylum, Female War, and Genocide). However, as befits most cases where mad scientists prove they are every bit as loony as the stereotypes dictate, the Rogue gets loose and causes havoc until it is torn apart by a Queen.


In Aliens vs. Predator: Extinction, a variation of the original Xenomorphs are created by Dr. Samuel Kadinsky. This group is called "The K-Series", as they are almost identical variants of the Xenomorphs. All that is different about them is that they are more aggressive and have a white skin color. The Xenomorphs on planet LV-742 kill the K-Series Hive, therefore killing a difficult obstacle.


In Aliens vs. Predator: Extinction, a Praetorian can evolve into two other forms of Xenomorph than just the Queen: the Carrier and the Ravager. The Carrier Xenomorph has the ability to carry 6 Facehuggers on spikes coming out of its back. Some can even carry 11 Facehuggers. Their vulnerability is their weak armor, but their greatest advantage is the Facehuggers they are carrying.

The Ravager Xenomorph's claws have the ability to kill enemies with one swipe. They can even cut through metal, and their powerful armor makes them impervious to all but the most intense assault. But its most astounding ability is that it can actually heal itself. The problem with this is that it takes time to regenerate, and this makes the Ravager vulnerable to attack.


The Alien has been portrayed in noticeably different ways throughout the films. Much of this is due to the technology and techniques used to bring it to life.

Body shape

In the original Alien film, Alien, they were depicted as tall, slender creatures with a roughly human silhouette and a biomechanical design. In later films, like Alien: Resurrection and Alien Vs Predator, they were depicted as being short and fleshy, portrayed by either men in suits or computer-generated imagery.


Originally, the Alien's tail was roughly the length of the creature with a small, almost surgical blade on the end. From Alien 3 onwards, however, the tail has grown in length and now features a massive blade at the very end. In Alien: Resurrection and Alien Vs Predator, the tails have also sported a fin right before the blade. This was introduced in A:R to help the creatures swim, and was left on in AvP as ADI, the company that made the creatures, didn't have enough time to re-do the tails.

Head shape

In Aliens the xenomorph was depicted as having ridges along its cranium, while all other creatures had smooth cowls covering their skull. In Alien: Resurrection and Alien Vs Predator, the head was shortened greatly to roughly have the original thirty-three inches. It was also made flat at the base, with little to no similarity to the originals.


In every movie, with the exception of Aliens, the creatures have had six fingers on their hands.


In Alien: Director's Cut, the alien originally had a second method of reproduction, whereby it could transform humans into eggs, as shown when Ripley discovers Brett and Dallas under the landing gear at the end of the film. This offered an origin for the eggs that didn't require a queen, which seems to have been superseded (some would say merely complemented) by the queen in Aliens. None of the other films have shown this angle. Although, in Alien³ another addition was made: that of a "super facehugger" that could impregnate two hosts with Queen and Runner embryos and was larger and darker compared to normal. This explains why both Ripley and the dog (originally an ox took this role) was impregnated from one egg. Also, the hugger in the first cut impregnated Newt and when Newt drowned the fetus crawled from her mouth and entered Ripley. The "super facehugger" was found by some of the inmates, who thought it a type of jelly-fish.


DNA assimilation

Many believe that chestbursters, while still in an embryonic stage, use the host's DNA to augment its own and acquire any useful traits that the host garnered through natural selection. This makes sense from an evolutionary standpoint, since the host is adapted to its environment, taking on some of its characteristics would further adapt the newborn alien to its new environment. This would essentially make all adult xenomorphs hybrid creatures. This idea was used in some novel and comic book spin-offs. Another explanation could be that since the eggs seem to be produced asexually, the embryo receives some of its chromosomes from its host to allow for biodiversity of the species.

Alien³ furthered this by having an alien embryo implanted into a dog, though it was an ox that pulled the EEV that was 'impregnated' in the original script. The xenomorphs of the first two films were all implanted in humans, and thus could walk in a bipedal formation; they also had foot-long spikes on their backs. The "dog-alien" of Alien 3 was visually very different from these, because it took on some of the DNA of its canine host. It appeared and moved in a somewhat panther-like way, did not have spikes on its back, was far more streamlined in appearance, and ran incredibly fast on four legs, rarely standing on two.

The xenomorphs of fourth Alien film were something of an exception, because they were far more human-like, to the point that the Alien Queen gave live birth to a "human-alien Hybrid": this was all because these aliens were created as the result of cloning experiments by the military, and were not the "true" form of the species, having admittedly been spliced with much human DNA. However, this was not as a result of the normal implantation-DNA assimilation process.

In various comics and the "Alien vs. Predator" video game series, this is taken a step further when a xenomorph embryo is implanted into a Yautja (Predator); the result is an Alien with Predator characteristics, a "Pred-alien". This hybrid stood on two legs, and had the basic body-outline of a Predator, having lost the elongated head shape. It also lacked the inner set of jaws characteristic of other xenomorphs, but sported a set of mandibles reminiscent of those of the Predator. This motif was also repeated at the end of the recent AvP: Aliens vs Predator film, largely based on the comic books and the video game series and written by the director of Resident Evil.


Many fans believe that the difference between the original alien from the first movie and the swarm in the second is that of a soldier alien vs. drone aliens and that the colony contains both. Others believe that there is no soldier/drone caste and that standard adults are suitable to do all needed tasks.

Most of this debate is due to the variances between the two xenomorph designs in the first and second movie, primarily the issue of the cowl. Other popular theories are that the xenomorph sheds its cowl after further maturity (xenomorphs in all movies but the second were less than three days old) or that it was simply a design choice for Aliens that had no actual significant meaning.


Some believe that the xenomorph contains an endoskeleton as well as an exoskeleton. The primary fuel for this debate is the xenomorph skull seen as a trophy in the movie Predator 2, but until AvP the two franchises were distinct, besides this nod to the Alien films. In the Aliens vs Predator comics the aliens have only an exoskeleton, but this skeleton can be bleached, e.g. when left in the sunlight (such as the queen's head trophy on Noguchi's roof at the end of Prey).

The extra gene

Although the 'DNA-theft' theory is popular, the idea of the xenomorphic embryo actually using DNA from the host is rather unlikely.

First of all some micro-tool would have to find a proper cell, find out what parts of the DNA can be used, then take out that part, then return to the embryo, then break apart the embryo's DNA, and build in the new parts.

Xenomorph are silicone based life forms, and adding the DNA of an organic lifeform into their DNA strand would be impossible, because the organic DNA would give the RNA instructions to build cells that simply would not function with the silicone based body of the xenomorph.

Adding an entire chromosome would have an equally distortive effect to the embryo.

A more logical explanation is that the facehugger releases a substance in the body, which can function on an equal level with DNA. This 'tool' could simply attach itself to the host's DNA, and proceed in giving codes to the RNA, which will then influence the build of the cells.

This additional gene could spread through the body rapidly as it lands in the bloodstream and gather information from all the DNA. This is necessary since for example the DNA that is found in the lung cells are only active for the lung part, while the information for any orther part of the body is dormant (another reason why it is a waste of energy and too much of a risk just to take the actual DNA of the host).

This extra gene would enable the host body to undergo alterations without ceasing to function, in a matter of fact, is seems to increase the endurance of the host body (referring to Purvis, Alien Resurrection). For example, the small 'womb' inside the lungs, serving to keep the lungs of the host intact and functional in the same manner as it did before. Also, by the walls of this womb, the embryo could be integrated with the gathered information from host. Therefore, the embryo would not be a hybrid, but merely be using copies of useful assets (also, it will not have to deal with the tons of junk DNA present in humans).

The alien gene is most like a tool that permanently attaches to the host cells, to keep them functioning as well as possible until the moment of 'birth'. Possibly, it could even multiply itself, which would be rather likely since to function with the host body it would have to be similar to the host body, meaning it would have adapted before spreading.

This gene stimulates the growth of the womb and the embryo, as well as the endurance of the host. Concluding from Alien Resurrection, it would in fact need to contain the entire DNA pattern of the embryo. This seems logical, since it needs it to compare to the host DNA.

Inserting this alien gene into the host, and waiting until it began it's work would also explain the period the facehugger remains on the face of the host.

In addition, it explains the existence of Ripley 1-8.


According to the computer game Aliens vs. Predator 2, xenomorphs utilize ultrasound for relatively long-distance communication. Xenomorph hives are built with smooth, rounded edges instead of rough, sharp edges because sound propagates better in such an environment. The skulls of xenomorphs act as sonic amplifiers for both boosting the transmission of messages and ensuring that incoming messages remain audible. This theory correlates with the Queen's massive head, since administrative duties would require greater transmission/receiving strength than normal xenomorphs.

The origins of the xenomorphs have never been fully explained in the films, but the expanded Alien literature has stated that the xenomorphs are bio-weapons genetically engineered by an ancient race called the "Space Jockeys". Little is known of this race except that they are purported to have created the xenomorphs to fight an ancient war. Alien eggs would be used as "bombs" on an enemy planet and then the xenomorphs would proceed to kill the entire population as they spawned. The xenomorphs were then genetically designed to die off, however eventually mutated and thrived even after killing their prey. The Space Jockeys were then killed by their own creations until none remained. A single member of the Space Jockey race escaped in a bio-weapons ship full of xenomorph eggs, but was himself infected with a xenomorph and died aboard. This is, presumably, the dead alien seen by the crew of the Nostromo. In Alien Vs. Predator, there is another origin of the Xenomorphs: one of the first human civilizations, a combination of Egyptian, Aztec, and Cambodian cultures was established with the help of the Yautja (Predators) who taught humans how to build, were worshiped as gods and every hundred years when the Yautja returned, humans were host to the Xenomorphs they hunted to show their supremacy, but a failed Hunt turned into a war in which this civilization was wiped out and the last Yautja Predator defeated the Xenomorph Aliens in a nuclear explosion. The connection between the 2 origins of the Xenomorphs is theoretically speculative and unknown.

According to a popular theory the level of development of the Chestpopper is dependant of whether or not its queen is genetically compatible to the host. The eggs, which spawned the facehugger that impregnated Executive Officer Kane (and afterwards the Chestbuster) of the Nostromo incident where laid by a queen that in turn came from a host belonging to the Jockey race. The Chestpopper came out slightly degenerate and underdeveloped. The Chestpopper from the Hadley’s Hope incident were lain by a Queen that was born from a human host (and therefore compatible with human genes) and were born from a human host. Therefore the Chestburster from the Hadley's Hope incident were more developed than the Chestpoppers from the Nostromo Incident. However, the Fury 161 'dog-popper' was born with legs, arms, a tail and a destinguishable head. If the theory was true, than the creature would've resembled the typical snake-like form of the chestpoppers seen previously.

External links

Alien movie series
Alien | Aliens | Alien³ | Alien: Resurrection
Alien vs. Predator
Relating to the Alien universe
Bishop | Ellen Ripley | LV-426 | Nostromo | United States Colonial Marines | Weyland-Yutani | Xenomorph | Yautja

Academic Kids Menu

  • Art and Cultures
    • Art (http://www.academickids.com/encyclopedia/index.php/Art)
    • Architecture (http://www.academickids.com/encyclopedia/index.php/Architecture)
    • Cultures (http://www.academickids.com/encyclopedia/index.php/Cultures)
    • Music (http://www.academickids.com/encyclopedia/index.php/Music)
    • Musical Instruments (http://academickids.com/encyclopedia/index.php/List_of_musical_instruments)
  • Biographies (http://www.academickids.com/encyclopedia/index.php/Biographies)
  • Clipart (http://www.academickids.com/encyclopedia/index.php/Clipart)
  • Geography (http://www.academickids.com/encyclopedia/index.php/Geography)
    • Countries of the World (http://www.academickids.com/encyclopedia/index.php/Countries)
    • Maps (http://www.academickids.com/encyclopedia/index.php/Maps)
    • Flags (http://www.academickids.com/encyclopedia/index.php/Flags)
    • Continents (http://www.academickids.com/encyclopedia/index.php/Continents)
  • History (http://www.academickids.com/encyclopedia/index.php/History)
    • Ancient Civilizations (http://www.academickids.com/encyclopedia/index.php/Ancient_Civilizations)
    • Industrial Revolution (http://www.academickids.com/encyclopedia/index.php/Industrial_Revolution)
    • Middle Ages (http://www.academickids.com/encyclopedia/index.php/Middle_Ages)
    • Prehistory (http://www.academickids.com/encyclopedia/index.php/Prehistory)
    • Renaissance (http://www.academickids.com/encyclopedia/index.php/Renaissance)
    • Timelines (http://www.academickids.com/encyclopedia/index.php/Timelines)
    • United States (http://www.academickids.com/encyclopedia/index.php/United_States)
    • Wars (http://www.academickids.com/encyclopedia/index.php/Wars)
    • World History (http://www.academickids.com/encyclopedia/index.php/History_of_the_world)
  • Human Body (http://www.academickids.com/encyclopedia/index.php/Human_Body)
  • Mathematics (http://www.academickids.com/encyclopedia/index.php/Mathematics)
  • Reference (http://www.academickids.com/encyclopedia/index.php/Reference)
  • Science (http://www.academickids.com/encyclopedia/index.php/Science)
    • Animals (http://www.academickids.com/encyclopedia/index.php/Animals)
    • Aviation (http://www.academickids.com/encyclopedia/index.php/Aviation)
    • Dinosaurs (http://www.academickids.com/encyclopedia/index.php/Dinosaurs)
    • Earth (http://www.academickids.com/encyclopedia/index.php/Earth)
    • Inventions (http://www.academickids.com/encyclopedia/index.php/Inventions)
    • Physical Science (http://www.academickids.com/encyclopedia/index.php/Physical_Science)
    • Plants (http://www.academickids.com/encyclopedia/index.php/Plants)
    • Scientists (http://www.academickids.com/encyclopedia/index.php/Scientists)
  • Social Studies (http://www.academickids.com/encyclopedia/index.php/Social_Studies)
    • Anthropology (http://www.academickids.com/encyclopedia/index.php/Anthropology)
    • Economics (http://www.academickids.com/encyclopedia/index.php/Economics)
    • Government (http://www.academickids.com/encyclopedia/index.php/Government)
    • Religion (http://www.academickids.com/encyclopedia/index.php/Religion)
    • Holidays (http://www.academickids.com/encyclopedia/index.php/Holidays)
  • Space and Astronomy
    • Solar System (http://www.academickids.com/encyclopedia/index.php/Solar_System)
    • Planets (http://www.academickids.com/encyclopedia/index.php/Planets)
  • Sports (http://www.academickids.com/encyclopedia/index.php/Sports)
  • Timelines (http://www.academickids.com/encyclopedia/index.php/Timelines)
  • Weather (http://www.academickids.com/encyclopedia/index.php/Weather)
  • US States (http://www.academickids.com/encyclopedia/index.php/US_States)


  • Home Page (http://academickids.com/encyclopedia/index.php)
  • Contact Us (http://www.academickids.com/encyclopedia/index.php/Contactus)

  • Clip Art (http://classroomclipart.com)
Personal tools