Atypical gnawing and cage destructive behavior in one strain of laboratory rat

Approximately 80% of a colony of 900 Long Evans rats, Blu:(LE), gnawed on polypropylene shoe box type cages around the automatic watering grommet. The gnawing led to cage destruction and escape of the animals. The addition of a large stainless steel shield between the original grommet backing and the cage prevented further gnawing on the cage.