L leopardinusGroup living is relatively common in animals and individuals in groups obtain benefits like enhanced feeding success and lowered predation risk. The assumption of “lack” of sociality in reptiles has been challenged lately and complex social systems have been recently documented in various lizard taxa. We study Liolaemus leopardinus, which lives at high-elevations, is viviparous, and is endemic to the central Chilean Andes. The social structure of this population appears to be family groups embedded within a larger colonial group. The speciesis long-lived (~10 y), not common for a medium-sized lizard. Its long life coincides well with the species’ slow growth, low metabolism, and long periods of inactivity, intermittent reproduction, non-aggressiveness, and small litter size. Most important, long life allows the formation of stable social groups among cohabiting conspecifics. Parental care is present and neonates may also receMadre con bebes closeupive care from other related and unrelated individuals, who form large social groups. The social groups seem mainly to serve the purpose of increased vigilance and protection from abundant avian predators; small neonates are very susceptible. Neonates recognize kin from scent alone, probably as a result of imprinting at a very early age. It is possible that after overwintering by themselves, neonates individually seek out specific chemical cues in the habitat and discriminate among the social groups located in the nearby rocky outcrops. Once the chemical cues of their mothers are identified, neonates join kin groups.