Earlier conjecture that revivification occurred only in humans was premature. Thanks to the discover of the substances ability to revivify large canines, the properties of XE-037 in mammalian organisms is now far more clear.
From what we can tell so far, exposure introduces a persistent, low level infection in mammal subjects, regardless of size or nature. The substance seems to multiply within the body until it reaches a certain point, and then enters a form of stasis and ceases to grow. It is, as yet, unknown why this halting process occurs in mammals, but not in insects - further research is needed. The body does not seem to attempt to combat the invader, and in fact no defenses have been noted - the body simply ignores the presence of the substance.
The spread seems to halt at roughly 1% of body mass, though exact numbers are difficult to determine thanks to the risk of mid-autopsy revivification.
The reason why earlier reports confined revivification to humans was that the process requires a critical amount of XE-037 within the body, not as a percent but as pure weight. Around half a pound seems to be enough to insure a post-mortem takeover. Animals small enough that 1% of body mass falls below this threshold thus fail to revivify, and the infection shrinks and then dies several hours after it’s host organism has passed. In larger animals, expiration seems to serve only to raise the cap on XE-037 within the body - expiration quickly leads to the XE-037 breaking down many of the now inactive bits of it’s host until it makes up almost 4% of body mass. At some point towards the end of this process, the host organism revives in the manner we are all, by now, familiar with, seemingly under the full control of the substance.
Infected subjects that sustain extreme trauma before death seem to exhibit lower growth level in
internal XE-037, which can be lower than the expected 4%. Revivification of subjects in such cases
is slower. This lead to the conclusion that XE-037 “prefers” less damaged corpses.
Additionally, damage beyond a certain threshold, such as the removal of several internal organs, quartering the corpse, or exposure to high explosive or heat, seems to overwhelm the XE-037 infection, causing the same dwindling and death behaviour seen in smaller organisms.
Observations that high-trauma revivification subjects are not noticeably different from low-trauma subjects have proven to be premature. The 93-XE series of studies has been designated for consolidating existing data and performing additional research after the labs have been repaired and personnel replaced.