Baby Yoshi

Baby Yoshi is a baby form of the regular adult Yoshi. In the New Super Mario Bros. games they often sign to the rhythm of the song playing in the background.

In canon
Baby Yoshis first appear in the game, Super Mario World, in Star World. They hatch from an egg, and need to eat five enemies in order to turn them into a fully-grown Yoshi. Eating one power-up makes them grow faster. Once they have fully-grown, depending on what color they are, they get unique abilites, but only eating a Koopa Troopa will give them this.