From the Super Mario Wiki, the Mario encyclopedia
In this form, the Yoshi can jump to grab items and avoid hazards; he moves much faster than in his normal form, especially on slopes. Like all forms, Yoshi only has a limited amount of time before he reverts to normal and is sent back to the door; clocks scattered about the obstacle course provide the Yoshi with more time. Going through a ring will simply return the Yoshi to normal.
Names in other languages