Defensive burying in two strains of rats selected for emotional reactivity

This paper examined defensive burying in Tsukuba High- and Low-Emotional rats (THE and TLE). The THE rats showed significantly more defensive burying and more immobility than the TLE rats. The TLE rats were more active and started prod-investigation faster than the THE rats. Some TLE rats bit the prod immediately after shock administration. No significant strain differences were observed in passive avoidance (stay away from the prod) and time spent at prod-investigation. The results indicate that THE rats are active and TLE rats are inactive in relation to defensive burying, although THE rats generally show passive coping. The relation between defensive burying and strain-specific coping styles is discussed.