EFFECTS OF NONCONTACT EXPOSURE TO RODENTS ON DEFENSIVE BEHAVIORS IN MICE

These experiments explored the effects of non-contact exposure to two rodent species (rats and gerbils) on the defensive behaviors of male C D-1 mice. In Experiment 1 it was found that rats evoked substantial le vels of defensiveness which were positively related to increases in ra t activity. This effect was considerably attenuated, but still detecta ble, 30 min after rat exposure (Experiment 2). In Experiment 3 the eff ectiveness of rats and gerbils were compared. Gerbils were found to ev oke a more modest increase in defensiveness than rats. These experimen ts indicate that non-contact exposure to rodents displaying varying le vels of activity and, perhaps, propensity for predatory behavior provi de a useful level of experimental control over the intensity of fear-l ike responses. (C) 1997 Elsevier Science B.V.