Ferret mothers provide more anogenital licking to male offspring: possible contribution to psychosexual differentiation.

European ferret (Mustela putorius furo) mothers displayed significantly higher levels of anogenital licking (AGL) towards male as opposed to female kits in tests given on postpartum (P) days 6, 12, and 15. In these tests the entire litter was removed from the nestbox for 10 min, whereupon individual male and female kits were reintroduced to the mother in a counterbalanced order. In a second study an analysis of videotapes, sampled over the 24 h of several days, showed that mothers provided significantly more AGL to males than to females on P15, with a similar trend being observed on P1 and P8. This difference was no longer present on P22. In neither experiment was any sex difference observed in the amount of maternal licking of other (nonanogenital) body parts or in maternal carrying behavior received by kits. These results are comparable to those previously published for rat and gerbil, and further emphasize the possible contribution of sex differences in maternal stimulation, especially AGL, to the development of sexually dimorphic features of brain and behavioral development in different mammalian orders.