Age-dependent social learning in a lizard

Evidence of social learning, whereby the actions of an animal facilitate the acquisition of new information by another, is taxonomically biased towards highly social mammals, especially primates and birds. However, social learning need not be limited to group-living animals because less social species can still benefit from learning about potential predators, food sources, rivals and mates. We trained male eastern water skinks (Eulamprus quoyii), a mostly solitary lizard from eastern Australia, in a two-step foraging task requiring innovative behaviour. Lizards belonging to ‘young’ and ‘old’ age classes were presented with a novel instrumental task (displacing a lid) and an association task (reward under blue lid). All lizards learnt to use innovative behaviour (displacing a lid from a well) to access food rewards, at similar rates. However, young males in the presence of a demonstrator learnt the association task faster than young males without a demonstrator, while old males in both treatments had similar success rates. We present the first evidence of age-dependent social learning in a lizard and suggest that the use of social information for learning novel problems may be more widespread than previously believed.