[Factors influencing the hunting success of a predator: a model with sighthounds].

Using microbiological criteria (the number of CFU in nose prints on agar medium), it has been shown that the proportion of individuals with a high CFU count is significantly higher among brown hares caught by sighthounds or exposed to immobilization stress than among shot hares. A hypothesis is proposed that metabolites of the body surface microflora in animals exposed to long-term stress account for their specific stress odor. Observations on wild hare coursing with the use of GPS tracking (1-s update rate) provide evidence that hunting success is not directly dependent on the absolute and relative coursing speeds, the number of sighthounds, and the distance, duration, and number of coursingevents. An analysis has been performed of stress odor as a universal criterion allowing the predator to estimate the vulnerability of potential prey. Selective elimination of unhealthy (stressed) individuals by predators is a mechanism of natural selection for increased adaptation of populations and species to the effects of a broad spectrum of environmental factors.