Maybe the dinosaurs evolved from birds?

Lex : [a Brachiosaur eats from the tree Grant, Lex and Tim are sleeping in] Go away!
Dr. Alan Grant : It's OK. It's OK. It's a Brachiosaur.
Tim : It's a veggiesaurus Lex! Veggiesaurus!
Lex : Veggie!
Lex : [Brachiosaurs hearing Grant imitate they're singing look up in his direction] Sh. Sh. Don't let the monsters come over here.
Dr. Alan Grant : They're not monsters, Lex. They're just animals. And these are herbivores.
Tim : That means they only eat vegetables, but for you I think they'd make an exception.
Lex : I hate the other kind.
Dr. Alan Grant : They just do what they do.
Lex : [the T-Rex has just killed a Gallimimus] I want to go now.
Dr. Alan Grant : Look how it eats.
Lex : Please!
Dr. Alan Grant : [to Tim] I bet you'll never look at birds the same way again.
Elephants are herbivores, too.
And Rhinos, and hippos, and...
...them bulls that chase after red capes.