God knows I'm not fond of the theory of the pack, for many reasons I've given (cf. hybridization) and I will sum it like this: if the "Beast" had been several animals, one would enventually have seen them together. The Beast was sometimes seen with a smaller canine, probably a wolf, but this second animal never took part in the killing. It would be wise to assume there was only one animal (and that it was no wolf), because the other animal seen with the beast was never witnessed in an attack.
The study I made about the wounds found on the animals killed during the case, shows one thing: it's pretty sure that both animals cross each other in Gévaudan during the first part of the case until september 1765, because the animals have wounds that have been done to "the Beast". But did they live in pack? How come these two big males were never seen together? Why did they never attack at the same time but not the same place?
I wanted to clear things, but they just got fuzzy, didn't they?
And yet, I haven't talked about the identical fur. That's something to drive you crazy! What's the problem? The problem is that there does noit seem to be an,y problem. Both animals have a fur of the same colour, same hair length, a white stain on the chest, a black strip on the spine, mid-long hair on the body, short hair on the face and legs. The colour is brownish, "stripped with dark rays" (c.f. : anecdotes).
Considering these conclusions, I've thought of a story. Nothing really serious, but let's see how we can make it work.
So let's imagine a duet of canine, maybe a father and his son? A wolf and his hybrid cub, the mother would have been killed one or two years before the case. At least they are from the same pack, best from the same family. I can easily imagine the old father getting killed by Antoine in september 1765 somewhere in Gévaudan, then brought to the forest of the Cazes for Antoine tricked hunt. So ends the old male, leaving the young one alone in the wild. Being more shy than his father, it will take him som time before he makes his first attack (that's why it's been quiet during the winter of 1765/1766), then slowly during the year 1766 he practises and finds himself a wolf-mate which he protects during next winter (quiet winter 1766/1767), and when spring 1767 comes as well as five cuibs he need to feed! The end of the second animal will be killed by Jean Chastel.
I don't beleive in sucha scenario, full of flaws and other improbabilities but who knows?
But that's only my own private personnal thought...