User blog comment:Mckrongs/Monster Hunter 4 for the Nintendo 3DS/@comment-4476693-20120925230358/@comment-4563270-20120926015434

@AWC actually i have theory about the feral wyvern virus on monsters. if you observe the gameplay against tigrex a NOOB with beginner armor and lance took out tigrex in 5 min. 5 MINUTES! no one beats tigrex in anything under 30 min. with beginner crap no matter how skilled you are.. Thus I conclude that any monster who contracts the feral wyvern virus has hp buffed to about half with no way to regenerate similar to how the hunter takes extra damage and can't regenerate red health when they contract the disease too.

However unlike the hunter when the monster contracts the virus they don't get the adrenaline boost that hunters get when health is low from the virus.. instead I theorize that the monster has to die first before it get's an adrenaline REVIVAL fueled entirely off of feral instinct from the virus thus the name feral wyvern virus.. hence why tigrex gets a mote demonic roar and tends to be more rampant than usual.. they go from fight/flight instinct to clouded judgement and rage attacks like tigrex and deviljho when in rage mode which may also mean when enraged you may have to make a final stand with the monster till their down as they won't leave the room at that point.