does anyone know why they started calling stanley caveman?

It's because Stanley found a 魚 fossil and was hoping to get the 日 off from Pendanski but was denied and X-Ray mentened that his was a neanderthal and since that scene he was known as "Caveman."

in the book he was really big and rough-looking, like a caveman. they had to put in the movie, regardless the Shia Labeof isn't all that big.

In the book they say he was big and looked like a caveman. Therefor the guys started callinh him 'Caveman'.

What is the answer