A Tale of Two Dinosaurs

How a 7 year old boy plays with 2 dinosaurs:

The big dinosaur eats the little dinosaur after a long battle

Dino 1: "RRRRAAWAAAAAWWWERRRRRRR"
Dino 2: "GRRRRRRRRRRRRR"
The dinosaurs then run into each other, bite each other, rip out each other's throat and throw each other across the room.  There is much screaming, growling, and various other sound effects.

How a 2 year old girl plays with the same 2 dinosaurs:

The dinosaurs play in the snow

Dino 1: "Hi, I'm a big daddy dinosaur.  What's your name."
Dino 2:  "Hi, I'm little orange dinosaur.  Do you want to sing with me?"
D1:  "Sure, how 'bout "Row Row Row Your Boat?"
D2:  "Yea!"
Dinosaurs proceed to dance and sing
D2:  "Hey, I know!  Let's go play in the snow!
D1:  "Yea! I love snow."
D2:  "I love you big daddy dinosaur."
D1:  "I love you too."
D2:  "I'm sad, lets talk"
D1:  "Okay little orange dinosaur.  You're a nice dinosaur."
D2   "I feel better.  Let's sing again."

Two Dinosaur Friends

How can they be the same species?  (the kids, not the dinosaurs)