From the master:
"Robert got into dinosaurs when he was about 3, as many children do. It's a power thing: Children like the idea of creatures that were much, much bigger and stronger than mommies and daddies are. If a little boy is doing something bad, such as deliberately pouring his apple juice onto the television remote-control device, a mommy or a daddy can simply snatch up the little boy and carry him, helpless, to his room. But they would not dare try this with Tyrannosaurus Rex. Tyrannosaurus Rex would glance down at Mommy or Daddy from a height of 40 feet and casually flick his tail sideways, and Mommy or Daddy would sail directly through the wall, leaving comical cartoon-style Mommy- or Daddy-shaped holes, and Tyrannosaurus Rex would calmly go back to pouring his apple juice onto the remote-control device.
So Robert spends a lot of time being a dinosaur."