They were awesome creatures, the great reptiles of eons and eras past. To modern eyes, they appear magnificent … grotesque … and terrifying. And in fact, it seems inconceivable that their dominance of the planet could ever have ended. But end it did … at the hands of an even mightier adversary: Change. It was, of course, nature that dealt the most severe blows. Over the yawning ages, the great beasts were beset in turn by drought … by flood … by fire … and ultimately, by ice. Nimbler, more resourceful species were able to adapt to these catastrophically shifting conditions, and survived. But the colossal reptiles were simply too ponderous, too inflexible to adapt.