Repoductive biology of the endangered African wild dog (Lycaon pictus) in captive and free-ranging populations: an endocrine, behavioural and demographic approach

Reproductive biology is an important component of any conservation strategy. In the endangered African wild dog (Lycaon pictus), declining populations are necessitating human intervention in a number of areas to ensure long-term survival of the species. In this study, the reproductive biology of wild dogs was investigated to expand the limited existing knowledge. The overall aims were to determine if wild dogs have similar characteristics to other canids in reproduction, and to determine how improved knowledge of reproduction can benefit both captive breeding and in situ conservation programs. We used a range of traditional and modern techniques, producing endocrine, behavioural and demographic data. Faecal samples were collected from females in four captive institutions in Europe, and from males and females at Hluhluwe-iMfolozi Park in South Africa, and radioimmunoassayed for oestradiol, progestagens, testosterone and glucocorticoids. Longitudinal hormonal profiles for captive females showed that wild dogs had similar characteristics of reproduction as other canid species, such as spontaneous ovulation and obligate pseudopregnancy. Almost all adult females became pseudopregnant, implying that the mechanism of reproductive suppression in this species is likely to be behavioural rather than physiological. This was further confirmed by hormonal and behavioural analysis of individuals in free-ranging populations, where differences in age led to some variation in hormone concentrations but not social status classes for adults. Adrenal activity in captive and free-ranging populations was determined by measuring faecal cortisol metabolites. Captive females had higher concentrations overall than free-ranging females. In captivity, individuals within zoos had variable faecal glucocorticoid concentrations whereas, in free-ranging populations, faecal glucocorticoids were highest during gestation and denning period in both males and females.