I watched the whole series and am enjoying it...
However, you said all mammals would die in an earlier episode (believe it was three...one with the tigress) so does that mean sabretooth tigers and the woolies are on the modern day creatures side? Next, was wondering how come we have no "magical" creatures like that pterodactyl thingy in number 4 (?). I think that although guns are good, maybe you should stick to a more ancient way of killing things (bows etc.) Anyways great stuff and love your work! =D