User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-6050823-20130206223334/@comment-5963861-20130210155423

^ I'm pretty sure they're just combining their attacks not mating. On the subject of them popping up from under eachother, judging by the videos I've seen they don't neccasarily do it at random, rather they do it when one of them is paralyzed or put to sleep. So it appears that they're protecting eachother and combining their attacks. Also they're pretty aware that the hunters are there and it wouldn't be wise to mate while you're under attack.