Yoshi first appeared in Super Mario World (SNES). In that game, Mario rides on him, and Yoshi darts out his very long tongue, eating countless enemies without gaining any weight, gaining you a coin for each one. It is unclear whether Yoshi refers to the species or the individual dinosaur, as it is used like a name, but it is used for every single one.

Yoshi was so popular that an entire game was later dedicated to him (Super Mario World 2: Yoshi's Island). In that, he tries to bring baby Mario and Luigi to their parents after they are kidnapped by baby Bowser. This game has its own sequel on the N64, but I never played it.

Yoshi has been in every Mario game since, even though it is often a minor part. He comes a wide range of colors, but is best known in his green form. In Super Mario World, different colored Yoshis have different abilities (blue is the best). In Yoshi's Island, they are simply an ethnically diverse but equal population.