No it's true, apparently (so I've heard) it's an easter egg, in the game, when you get to a certain level you encounter giant varieties of kagouti and such near vos in the gravelands along the mountain ranges.
Damn that's a helluva guar, bet it don't smell too good neither. Thanks for post and the pic tranquility, I hope you don't mind but I'm going to move this to the spoilers section, just in case.
I've been told that bethesda put this into the game but if I'm wrong feel free to correct me.