Ms. Devilliers et al., SOCIAL DYNAMICS AND THE CORTISOL RESPONSE TO IMMOBILIZATION STRESS OFTHE AFRICAN WILD DOG, LYCAON-PICTUS, Hormones and behavior, 31(1), 1997, pp. 3-14
The aims of the study were to characterize the cortisol response to im
mobilization stress in African wild dogs (Lycaon pictus) and to invest
igate the relationship between stress and sociality in these pack-livi
ng canids. Ad lib. observations were made on a captive pack of 19 wild
dogs. Individuals were classified as either dominant or subordinate.
Cardinal and ordinal dominance indices were also calculated for pack m
embers, as were three other behavioral indices. Active and passive dom
inance styles were distinguished. Serial blood samples were drawn from
animals after chemical immobilization and again after ACTH challenge.
The relationship among rank, plasma cortisol concentration, and behav
ioral style was investigated. When data were combined over the entire
study period, there was no obvious relationship between rank and corti
sol concentrations or cortisol responsiveness to immobilization stress
. Instead, younger animals had higher cortisol concentrations than old
er ones. Age cohorts were also clearly separated on the basis of behav
ioral profiles. For males, these distinctions among age classes were e
specially apparent during the second part of the study period, when su
badults occupied dominant positions in the hierarchy. Adult males main
tained relatively low cortisol concentrations, despite being involved
in and losing a high proportion of dominance interactions. Age-related
differences in cortisol profiles of dominant individuals may be expla
ined by differences in the style of dominance employed, with younger m
ales using proportionately more active dominance (threats used to elic
it submission). The separation of age classes according to rank, behav
ioral styles, and cortisol concentrations may reflect improved social
skillfulness with age. (C) 1997 Academic Press.