Why are all the ‘prehistoric’ versions of animals so massive?

Question

We always hear about how big ancient sharks, alligators, birds were. What was the advantage of being such a massive size and what caused them to become smaller? To my understanding its best to be smaller because of the square-cube law, then why are there exceptions like whales?

In: 3

Answer 1

Some were smaller, some were bigger, some were the same. The ones that were bigger are “cooler” and are better preserved in fossils so you hear of them more.