PhenoTyper is a complete video-based observation system that is used with laboratory rodents. PhenoTyper is a combination of a cage and a top unit with light, sound, and video. Each configuration consists of a bottom plate, four replaceable walls, and a PhenoTyper top unit. Walls are transparent but can be replaced by (partially) opaque/matted walls to reduce reflection. Optional wall attachments are available, such as a feeder (with IR-based feeding monitor), bottle holder (with capacitance-based drinking monitor), pellet dispenser, shelters and CognitionWall (for learning experiments). PhenoTyper is available in two standard sizes with floor areas of 30cm x 30cm or 45cm x 45cm. Custom sizing is also possible. The instrumented top unit contains an infrared sensitive camera with three arrays of infrared LED lights. Light conditions can be adjusted experimentally, as can the single tone for operant conditioning tests, and the white spot light for approach-avoidance behavior testing.