Because they secretly traveled in time to find the tradition of Christmas and when they came back they decided to celebrate it. That or the writers of the show just didn't know history.

by Anonymous 13 years ago

I have so asked this question before xD But really, dinosaurs and homo erectus is chronologically unsound to begin with, so it's best to just let the absurdity of cartoon shows go. It's like all those people bitching about campfires in Bikini Bottom lol

by Anonymous 13 years ago