Olfactory discrimination in scat-piling lizards

Several lizard species in the Australian scincid genus Egernia have been reported to deposit seats in piles. We show that E. striolata, which does produce seat piles, and E. inornata, which does not, can both discriminate their own secretions, on paper substrates, from those of unfamiliar conspecifics. This was indicated by elevated tongue flick rates and more time in contact with the unfamiliar stimulus. This was not just a response to a novel stimulus because the secretions from another species (E. stokesii) elicited lower responses. When seats were presented, only striolata demonstrated discrimination between their own seats and those of unfamiliar conspecifics. This suggests that seats could be used to produce individual signals, perhaps indicating residence status, in seat-piling species. For striolata the signal from seats became less effective as the seats became older, suggesting the need to pile seats to renew the signal.