Is there any indication given in the Alien movies or literature of how long an Xenomorph lives for? It occurred to me that given a limited number of potential hosts ( as per the colony on LV-426, the number of suitable gestation vessels would soon be depleted as would any other sources of food.

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    First, I think you'd have to distinguish between lifespan and life-cycle. Next, it would depend on (a) which stage of the lifecycle the xenomorph is in--dormant egg, facehugger, then full xenomorph; (b) which xenomorph it is in particular--they're eusocial, so it's likely that there are more than simply queen (whose lifespan would be different) and workers; and, (c) whether these were 'pure' xenomorphs' (if they even exist) or 'morphs', like the 'dog alien' or the others that supposedly existed before the xenomorph in the first film (the deacon of Prometheus or the neomorph of Covenant).
    – wcullen
    Commented Mar 26, 2018 at 16:40
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    @wcullen fair point, I was talking purely about lifespan. Perhaps, as we find out in Covenant, any non botanic life is a suitable host, its life span is linked to that of the original host from where it was born. None the less, without an abundant source of food, it would seem logical that life span would be cut short.
    – GeoSword
    Commented Mar 27, 2018 at 5:42
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    @GeoSword In regards to lifespan I was also thinking about diapause--esp. as it can occur at any stage of development. This would alter the lifespan. Here I'm thinking of the original film and how long the eggs may have been in diapause before the crew of the Nostromo visited the LV-426 (following this, I wonder what acted as the quiescent trigger for the xenommorphs...if there is one). A significant aspect of the xenomorphs is clearly based upon parasitoid insects esp. Eucharitidae. I see Prometheus as Scott's tip-of-the-hat to E.O. Wilson's convergence/emergence influence :-)
    – wcullen
    Commented Mar 27, 2018 at 6:49
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    @GeoSword By way of FYI--there was also a similar discussion on this topic here: scifi.stackexchange.com/questions/97309/…
    – wcullen
    Commented Mar 27, 2018 at 6:51
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    About one Ripley.
    – Zeiss Ikon
    Commented Feb 27, 2020 at 17:51

2 Answers 2


Ripley claims in "Aliens" that "one of those things managed to wipe out my entire crew in less than 24 hours".

I presume that the first Alien film shows us the entire cycle of egg hatching, implantation by facehugger, chestburster and xeno taking crew members (to cocoon them and transform them into eggs it seems), over a period of 2-3 days max. (One for the setting down on LV-426 and facehugging, and 8 hrs plus for Kane to be unconscious, and then the 24hr period while the alien hunted them out one by one on the Nostromo).

A maximum of 48-72 hours seems reasonable for these events to have taken place, even if there's no concrete information in the script or novelisation as to exactly how long the time period is from first contact to the expulsion of the alien from the Narcissus... and although we don't know for sure how long the alien would have remained alive if not killed, there is a mention on the DVD commentary about the idea that the alien was "sleeping" inside the shuttle because it was nearing the end of its natural life cycle and looking for a place to curl up and die.

The periods of gestation and hatching seem to get even shorter in more recent films (although my knowledge of books and comics is too limited to comment on those), but speaking of the first and second film, the xeno stage's life seems to be around 3 days or so if it was ready to die by the end of the first movie's events, and in "Aliens", the adult warriors appear to be in a hibernation state in their nest, semi-lodged into the walls.

If taking into account the idea of the lifespan of the xeno from egg to adult form, though, this could be hundreds, or even thousands of years to include the egg-stage dormancy. The adult form is evidently quite short-lived in comparison.

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    This couldn't be. On the second movie the marine squad is dispatched to check what's happening with the settlement, where contact has been lost. The spatial travel takes enough time to require crew hibernation, however, when they reach the settlement, hundreds (if not thousands) of specimens are alive. Their life expectance is not known and we cannot infere it by what we've seen on the movies.
    – Bardo
    Commented Aug 25, 2020 at 8:34
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    @Bardo however, there are also colonists that are still “birthing” new aliens when the marines get there, so who knows?
    – Moo
    Commented May 22, 2021 at 8:57
  • @moo interesting hypothesis. will the aliens keep potential hosts alive for as long as possible before implantation in order to quickly produce fresh soldiers if needed?
    – Xantec
    Commented Sep 19, 2021 at 10:14

I was watching a video on Alien and they said that the Xenomorph wasn't hunting Ripley when it was in the escape pod, rather it was looking for a quiet place to die. They said the color change (light to dark) was showing it's lifespan, the older it got the darker it got. I have yet to fact check this but I found it on youtube. The name of it is 25 things you didn't know about Alien (read the exact claim in this page), also see the video, you can find the exact spot at 12 minutes and 31 seconds into the video. Youtube wasn't working so I had to use a different site.

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    If you can provide an actual reference (and not a buzzfeed lookalike site) to one of the authors of Alien saying this, this could be a great answer).
    – Andres F.
    Commented Feb 27, 2020 at 17:55
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    Could you provide a link to the YouTube video in question? Right now your only link is to WhatCulture - not even their article about Alien, just the homepage - and as a result your answer looks like spam.
    – F1Krazy
    Commented Feb 27, 2020 at 18:17
  • Here is the link invidio.us/watch?v=2BoNbhp6JVM I had to use a different site because youtube wasn't working. It is at 12:31
    – Bdog
    Commented Feb 27, 2020 at 20:23
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    I've read the site and it unfortunately cites vague sources, such as a "making of book" and "some comments by Ridley Scott".
    – Andres F.
    Commented Feb 27, 2020 at 21:55
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    "I have yet to fact check this but I found it on youtube" - oh, well then, it must be true. Commented Feb 28, 2020 at 10:23

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