ИСТИНА

The phenomenon of over-marking, when animals deposit their own excreta on the top and nearby the odors left by another individuals, is well documented for many mammalian species.However, it still remains unclear what happens with individual scents in a course of over-marking when a complex mark is forming and what information animals are able to get during its’ investigation. The goal of the study was to estimate a principal ability of golden and Djungarian hamster males with the use of “Habituation-Discrimination” test: 1) to distinguish the addition of a new urine sample to a mixture consisted of 2-10 individual samples (N; “N+1”, and 2) to recognize an individual urine sample that is part of a mixture (“1 from N”). In both species a number of subjects showing discrimination of appropriate sample decreased with increase of a complexity of mixture. High correlation between males’ discriminative abilities in both tests was found. We’ve named the abilities to distinguish appearance of a new sample in the mixture as well as to discriminate one of the components of the mixture as chemoanalytical abilities because they are based on memory and analysis. Repeated testing revealed that chemoanalytical abilities are stable feature of a subject, do not depend on its’ hormonal state and a sex of urine donors. Our data allow to suggest that during investigation of odor mixture and, at least complex urine scent marks, animals perceive them as a set of discrete individually distinctive units.