Board Thread:Warhammer 40k General Discussion/@comment-46.162.84.254-20130704080553/@comment-6078851-20140714152002

it's stated in the tyranid codex that they originated in another galaxy, that's official, but it does state clearly that it's unknown if they have consumed many galaxies or if they have only consumed one.

it's also stated that they consume all available bio-mass in a galaxy and then move on. they don't hang around in a foodless galaxy waiting for scouts to report if another galaxy is viable - they immediately move on to the next nearest galaxy, enter hibernation, then if scouts find bio-mass in the next galaxy then that's where they go. if scouts find nothing then the bulk of the race stays in hibernation until the next viable food-source is reached.

i never said that every tyranid is heading here. i'm of the opinion that once a galaxy has been emptied of bio-mass they split up and head to multiple galaxies, because i think they are possibly the oldest lifeform in existence, and as such the hive-mind knows that a single galaxy would be to small to contain the whole race :P

i think there's misunderstanding on what is meant by bio-mass - everything that's organic, as well as god knows how many minerals, is a viable bio-mass source. so every form of life, whether it's alive or dead, is viable (even bacteria, of which the galaxy is teeming with - think blue whales and krill). coal, oil and gas, are all organic in nature and therefore viable sources of bio-mass. plus, because they, like most life, require minerals then even the technology of the milky way's races are at risk of being consumable. the necrons could destroy a lot, but they can't remove such stuff from existance, and even if all bio-mass was reduced to a molecular level it's still viable for consumption. this is what makes them so unmatchable in a war of attrition, the fact that they can consume so much whereas most other life can only consume select stuff and everything else is toxic on some level. plus, as i mentioned, they don't actually need anything to simply sustain their numbers as they can, and do, recycle their own organisms.

some codex quotes: "...a foe so terrible and single-minded that unless every race in the galaxy unites in opposition, it will destroy all life, all civilisation."

"the tyranids' numbers are beyond imagining, a swarm so vast that it blocks out the very stars."

"the tyranids do not communicate with other races, and why should they do so? tyranids are as far above life forms such as mankind as mankind is above the domesticated livestock it consumes."