Scent-marking and cortisol response in the small-eared bushbaby (Otolemur garnettii)

Among prosimians, some types of scent-marking may serve as displacement activities that reduce physiological arousal in stressful situations. Type and frequency of scent-marking was measured for 22 male small-eared or Garnett's bushbabies (Otolemur garnettii) exposed to a novel open field environment, with and without novel objects. Rates of foot rubbing, chest rubbing, urine washing, flank rubbing, and ano-genital marking were measured. Foot and chest rubbing constituted 92.5% of responses. Type and frequency of scent-marking was compared to the magnitude of the animals' cortisol responses in a separate test of restraint stress. Only foot and chest rubbing were systematically related to cortisol levels. The animals that performed these behaviors more in the novel environment also exhibited lower cortisol responses to restraint stress. These results suggest that bushbabies that characteristically employ behavioral coping strategies have a reduced physiological response to psychological stressors.