Following removal of their olfactory bulbs, virgin female rats consistently attack and kill rat young whereas non-lactating anosmic primiparous animals do not. The present studies were undertaken to compare the effects of bulbectomy on maternal behaviour in the parous and virgin female rat, and to analyse those experiences responsible for the marked behavioural differences towards young seen in these two groups.
Adult female Wistar rats, maintained by random breeding within a closed colony in the laboratory of M. X. Zarrow since 1949 (W/Z strain), were individually housed in 15 × 10 × 7 in. stainless steel cages under a 13-hr light/11-hr dark regimen (lights on at 07.00 hours), and at an ambient temperature of 70 to 74° F. Food and water were freely supplied. The virgin and non-lactating