Their ages....
I have the story book to go along with the video and it lists all the character's ages:
Alligator- age five
Johnny- age seven
Pierre- age seven
Chicken Soup- age eight
Kathy- age eight
Rosie- age ten
I just wanted to say that Kathy and Rosie look older than eight and ten. Well, at least Rosie because she's tall for a 10-year-old! XD