Exer-3/6 is a general purpose three (rats) or six (mice) lane animal exerciser utilizing single belt construction with dividing walls suspended over the tread surface. Exer-3/6 can be supplied with or without a stimulus assembly. An electrical stimulus system option is composed of three or six shock grids, each with individual on/off switches. Stimulus intensity is adjustable and LED lamps indicate which stimulus grid is active. Design of electrical stimulus grid reflects special attention to avoid injuries to animals. Animals are exercised in three or six compartments made of durable plastic (clear Lexan or opaque PVC). For some applications, users may choose to purchase Exer-3/6 with a single large compartment. An included drive motor controller provides smooth and continuous adjustment of speed in the range 2-102 m/m. The exercising belt is made with special material that facilitates the animals' grip and is easy to clean.