No, not all excavators have wheels! Some excavators have wheels, and some have tracks, which are like big flat pads that help them drive on soft or bumpy ground.
Imagine a toy truck that rolls on wheels. Now think of a big robot with wide feet that can walk over mud without getting stuck. Those wide feet are kind of like the tracks on some excavators!
Wheeled excavators can move fast on smooth roads, while tracked excavators are better for working in places like farms or construction sites where the ground might be uneven. So, depending on their job, excavators can wear wheels or tracks!