Summary: McCarty & Southwick (1977)

The physical and behavioural development of young mammals can be influenced by characteristics of the preweaning environment, particularly interactions with parents. Cross-fostering young (shortly after birth) between strains or species allows these parental influences to be assessed. If the behaviour of an offspring is similar to that of its foster parents, and is different to that of other individuals raised by their natural parents, it is suggested that parental interactions influence that behaviour. McCarty & Southwick (1977) examined the influence of cross-fostering on olfactory preferences in two species of mouse, the southern grasshopper mouse (Onychomys torridus) and the white-footed mouse (Peromyscus leucopus). Young were either cross-fostered or raised by their natural parents. 1 male and 1 female from each litter were then assessed in an olfactory preference task, where they were exposed to the odour of an opposite sex adult from each species. They found that both southern grasshopper mice and white-footed mice raised by their natural parents showed a preference for the odour of conspecific adults, whereas mice raised by foster white-footed mouse parents showed a preference for the odour of the heterospecific adults. They suggest that there is an interaction between the underlying genotype and preweaning parental interaction that influences the development of species-characteristic odour preferences.