Chemical recognition of familiar vs. unfamiliar conspecifics by juvenile iguanid lizards, Ctenosaura similis

The ability of juvenile black iguanas, Ctenosaura similis, to discriminate between the chemical cue of an unfamiliar and a familiar conspecific was te sted. Lizards directed significantly more tongue extrusions toward the chem ical cue of a size-matched conspecific with whom they had never interacted than the chemical cue of a size-matched conspecific with whom they had inte racted for 3 d. We consider the possibility that the social relationship be tween familiar associates may explain variation in the direction and degree of response to unfamiliar vs. familiar chemical cues.