The ethological relevance of predator odors to induce changes in prey species

Abstract

Predator odors are non-intrusive naturalistic stressors of high ethological relevance. Prey species show specific adaptations that allow recognition, avoidance, and defense against predators. For many mammalian species, this includes sensitivity towards predator-derived odors. The typical sources of such odors include predator skin and fur, urine, feces, and anal gland secretions. Avoidance of predator odors has been observed in many mammalian prey species including rats, mice, and voles. Field and laboratory studies show that predator odors have distinctive behavioral effects which include (1) inhibition of or decreased activity; (2) suppression of non-defensive behaviors such as foraging, feeding, and grooming; and (3) shifts to safe habitats or secured locations where such odors are not present. Chronic exposure to predator odor may elicit one of two controversial processes: sensitization and habituation. Some studies have suggested that chronic exposure to predator odors may induce behavioral sensitization while others stated little or even no habituation at all. Finally, prey species respond variably to different degrees of threats, and the odor intensity is a key factor to determine the “optimal” behavioral response. Future research should aim at linking behavioral and neuroendocrine changes for a better understanding of predator–prey interactions.