The age of olfactory cues functioning in chemocommunication among male domestic cats.

In a simulated open-field situation we tried to obtain information about the ability of tomcats to distinguish between urine marks of differing ages. Reactions to these marks were sniffing, sniffing intensively and "Flehmen". The variables we chose to demonstrate a possible discriminatory ability between urine marks of different ages were: (1) latency, i.e. the time that elapses between the cat's release in the observation arena and the finding of a urine mark, (2) the number of occurrences of Flehmen after sniffing, (3) the frequency of sniffing and Flehmen, (4) the duration of the first sniffing bout and (5) the occurrence of a return to the same scent source during an observation. Our most striking observation was that fresh urine marks (maximum age, 4 hours) were explored first, before marks more than one day old; the other variables did not differ dramatically although we observed a general decline in the intensity of the reaction with increasing age of the urine marks. We also found that the visual characteristics of a urine mark play an important role, particularly in the occurrence of returns. Furthermore we found that the reactions of sniffing and Flehmen are linked with an attempt to identify the donor. All results, including the possible influence upon marking behaviour of the presence or absence of fresh marks, are discussed in the light of the use of a "time plan" spacing mechanism by the domestic tomcat as had been suggested in earlier literature.