Stability of chemical communicants in urine: Individual identity and age of sample.

Male guinea pigs differentiated between fresh female urine and the same urine aged for 3 hr. Additionally, when tested with an habituation paradigm, they exhibited no evidence of recognizing fresh urine and the same urine aged for 3 hr as coming from the same animal. Males preferred the urine of a strange male compared to their own urine when the urine was fresh, aged for 2 hr or aged for 3 days, but not when the urine was aged for 8 days. These results suggest that the urinary cues of individual identity are not stable and that males have learned to recognize the modifications of their own urine which result from aging. In addition, it was found that changes in urine following aging make it possible for male guinea pigs to discriminate between urine samples aged for different amounts of time.