An animal monitoring device and method comprising an animal cage and associated electronics slab is described. The device is suitable for use in a modular vivarium implemented in one or two racks adjacent to walls in a holding pod. There is a one-to-one relationship between fixed slabs and removable cages. A single camera provides range of functions: its field of view includes the entire area of the cage accessible to an animal; it may observe water level in a water bottle; it may observe food level in a food tray; it may view activity on an exercise device; it may read the rear of cage card. The shape of the food tray is specialized to meet these requirements. An inner-cage frame holds elements in fixed locations within the cage. The cage is free of electronic penetrations. Supply and return air for the cage passes through the slab.