Effects of age and experience on reproductive performance of captive red wolves (Canis rufus)

Abstract

Propagation programs contribute to the conservation of a species by preserving genetic and demographic stock that may be used to reinforce or re-establish wild populations. Identifying traits that affect reproductive success is essential to achieve this goal. Longitudinal reproductive events of the captive population of endangered red wolves (Canis rufus Audubon and Bachman, 1851) were investigated to determine whether parental age, breeding experience, and rearing type were factors in reproduction, litter size, and sex ratio, as well as viability of offspring. Younger wolves were more likely to reproduce and produce larger litters than were older individuals. The age of the female, but not the male, had a negative effect on pup survival. Wolves that had prior experience in offspring production were more likely to reproduce again than were individuals that had no prior reproductive success, but prior sexual experience alone was not a factor in offspring production. Parental breeding experience had a negative effect on pup survival, but no apparent relationships with litter size or sex ratio. Declines in reproduction, fitness, and survival with advancing age suggest the effect is due to senescence, the onset of which occurs at 8 years of age in females. The results are consistent with the breeding-experience hypothesis.