Rat Monitoring Cage is 14 inches in height. The floor measures 9 by 9 inches, giving suitable room for a freely moving adult rat. The slide out lid has a 1.25 inch wide by 4 inch long slit to allow unobstructed pass through of any tethered line, yet inhibits the rodent from escaping. Seven 1.25 inch holes in the lid allow for adequate air exchange. The bottom of the cage has six 0.5 inch diameter dowels spaced 0.90 inches apart. When the cage is lifted out of its tray, this patent pending design allows for sufficient support for even the heaviest of adult rats, while allowing soiled bedding to fall into the tray below.