Happy Birthday to you, you belong in a zooDiane deGroat, Diane De GroatGilbert and Friends

Characters in Happy Birthday to you, you belong in a zoo

3 characters, main characters first.

Main characters

Gilbert
Also in April Fool! watch out at school!, Good night, sleep tight, don't let the bedbugs bite, Last one in is a rotten egg!, Liar, liar, pants on fire, Mother, You're the Best!, Trick or treat, smell my feet

Supporting characters

Sergeant Lewis
Gilbert's mother