""Yoshi made his debut in Super Mario World as a native dinosaur that Mario or Luigi could ride on in order to eat enemies and otherwise navigate Dinosaur Land more quickly and easily. This game spawned a prequel entitled Super Mario World 2: Yoshi's Island for the Super Nintendo in which the player could control Yoshi in order to keep Baby Mario out of harm's way as they advanced through the game. This led to a spin-off series of games including Yoshi's Story for the Nintendo 64, Yoshi's Universal Gravitation for the Game Boy Advance, and a number of games for the Nintendo DS, including Yoshi Touch & Go, and Yoshi's Island DS and Super Mario 64 DS.""
Source: Wikipedia, "Yoshi_(series)", available under the CC-BY-SA License.