Infant-mother recognition in a social rodent (Octodon degus).

Octodon degus (degu), a biparental species with precocious offspring is a potential model for the study of social attachment and related affective disorders such as depression. This study investigates the nature of the social bond between young degus and their mothers with a special emphasis on infant-mother recognition. We tested young degus in a potentiation paradigm to determine if social contact, particularly with the mother, can modulate an infant's vocal response to isolation. One week later, animals were presented with a choice between their mother and an unfamiliar female or a sample of familiar and unfamiliar nesting materials. Subsequently, the ability of whole litters to discriminate between their mother and unfamiliar females was tested. We observed that infant degus alter their isolation response after brief social contact. Degu infants readily distinguish between familiar and unfamiliar nesting materials but fail to differentiate between their mother and unfamiliar females in an identical setting. Nevertheless, entire litters show a preference for their mothers when tested similarly in a group, demonstrating a perhaps socially facilitated ability to recognize the biological mother at an early age.