This article discusses why the study of earthworms has fascinated many scientists, and why earthworms make ideal experimental animals for students to test in the laboratory. Although earthworms may appear to be primitive, they are governed by both circadian and seasonal rhythms, just as more advanced organisms are. They possess an intelligence that enables them to decide the placement and angle of implements with which to plug their burrows and sense organs that allow them to react to a variety of stimuli. Utilizing earthworms for experiments allows students to follow in Charles Darwin's legendary footsteps and also to enter into the realm of scientific thought. (Contains 2 figures.)