The immobility response elicited by clamping, bandaging and grasping in the Mongolian gerbil (Meriones unguiculatus)

When grasped by the skin of the nape and lifted into the air, the young of many altricial mammals exhibit an immobility response in which they tuck their limbs against their bodies and remain inert. Such a response can be induced in the adults of some species, especially if a stronger tactile stimulus such as bandaging the head and neck or clamping the skin of the nape, is applied. In this study, the immobility response of the Mongolian gerbil (Meriones unguiculatus) is investigated, which appears to differ in potentially useful ways from other commonly studied species such as rats (Rattus norvegicus). It has been previously reported that for rats clamping or bandaging had a more profound effect on the immobility response than grasping. Mongolian gerbils were tested will all three methods (grasping, bandaging and clamping), which were repeated at intertrial intervals ranging from 3 h to 40 days. Grasping induced a significantly longer duration of immobility than either bandaging or clamping. However, repeated trials significantly increased the duration of immobility induced by clamping, whereas repeated grasping or bandaging did not do so. The marked difference in the induction of the immobility response in gerbils as compared to rats, may provide a useful model for the study of this behavior.