Yoshi first appeared in [[Super Mario World]], when Bowser launched his biggest assault yet against Dinosaur Land. To eliminate the threat of Yoshi, Bowser magically encased the green dinosaur and his friends in Yoshi Eggs. Many of these eggs were given to Bowser's own children, the [[Koopalings]], to be watched over. Fortunately, for some reason, Green Yoshi's egg escaped the confines of one of the Koopalings' castles. Instead, Yoshi's egg prison wound up in a forest of [[Yoshi's Island]]. If Mario is hit while riding Yoshi, the dinosaur will yelp and run off scared and turn around when it hits something.  Only able to be reclaimed if Mario hops back on. After defeating Bowser and the Koopalings, Mario, Luigi, Yoshi, and [[Peach]] return will all the eggs to Yoshi's House to wath them hatch into newborn, baby Yoshi's..

Mario can find baby red, blue, and yellow yoshi's in star world (in the gba version of super mario world you can find these colored yoshis in other places in dinosaur land) which can be fed to transform into adult colored Yoshi's, all of which can use their color-coded power up no matter what shell they eat, plus the power-up of the shell. For example, A blue yoshi swallows a red shell, so now it can fly and breathe fire. (but if you have a green yoshi you have to hold that colored shell in your mouth to obtain that power.)