"Second, it's unlikely that the same creature has lived in the loch since the last ice age." is the best supporting passage for the idea that Nessie is not a plesiousaur. This is because any creature would have died by now from any number of causes. The loch is not large enough to maintain that big and ancient of a creature for such a long time. There would have been more sightings or it would have been found by now if it had been in the lake since the last ice age which occurred over 12,000 to 2,000,000 years ago.
