Mesozoic - the heyday of life?

[DSFPortree@aol.com]

I'm working on another dinosaur script idea for EARTH & SKY radio - seems to
me that, in many ways, life on Earth took a downturn after the Mesozoic.
Animals now are generally smaller. Some would argue they're slower, too. They
don't have as big and varied an arsenal of weaponry, offensive and defensive,
as did the dinosaurs.

Of course, nowadays we have humans, and humans have nuclear bombs, stealth
bombers, and the like, but I'm thinking of non-human animals here. Mammalia
has never produced anything on the scale of a Brachiasaurus or Tyrannosaurus
Rex. 

At least that's my impression. I wonder if anyone else has thought about
this. 

David Portree