The ability to discriminate kin from nonkin is critical for the evolution of kin-based sociality. Black rock skinks, Egernia saxatilis, are viviparous lizards that typically live in "nuclear families" consisting of an adult male, adult female, and one or more cohorts of juveniles. Laboratory trials showed that juvenile lizards can discriminate between the scent of adults from their own social group versus that of unfamiliar adults. Experiments in which we translocated individuals among family groups revealed that this discriminatory ability was based on familiarity with other individuals rather than genetic relatedness. For example, neither "fostered" juveniles nor their mothers displayed any scent-based kin discrimination when brought together after 2 months' separation. Thus, unlike the closely related (and also social) Egernia striolata, black rock skinks base kin discrimination on familiarity rather than genotypic similarity.
- kin discrimination