Effect of reproductive status on foraging behavior and fecal glucocorticoid metabolite levels in wild bat-eared foxes (Otocyon megalotis)

Abstract

Diet may be fundamental to the extensive paternal care and reduced maternal care seen in bat-eared foxes (Otocyon megalotis). This termite-specialist would struggle to increase its energy intake by hunting large prey or provisioning such items to mates or pups. Consequently, lactating, physiologically challenged females need to invest more time in foraging, while males spend time with pups. However, there is little empirical evidence of the impacts of parental care on foraging behavior and stress-related hormone levels in free-living bat-eared foxes. We studied foraging behavior in 20 wild bat-eared foxes for 2 years, investigating how foraging behavior and fecal glucocorticoid metabolite (fGCM) levels varied with austral season in the study population. Thereafter, we evaluated how parental status may affect foraging rates, food sizes consumed, and fGCM levels as a proxy for physiological stress. We examined these changes in parents (n = 3) and non-parents (n = 17) as seasonal “activity” changed—that is, breeding season (pregnant phase), denning season (pup-rearing and guarding phase), and non-breeding season (independent adult phase). Small item consumption patterns mirrored overall foraging rates, which were lowest for all foxes in winter. Males increased foraging rates in spring, while all individuals ate more large items in summer. Mean fGCM levels in the population (0.41 µg g−1 organic content) were not affected by sex or austral season, but changed with seasonal activities, for parents in particular: parents had significantly lower fGCM levels in the breeding season. This may reflect reduced stress in these foxes, who successfully paired and increased their within-family socialization during the breeding season. Our findings suggest that behavioral adaptations, including foraging adaptations, are sufficient for bat-eared foxes to meet the physiological challenges of parenting. This is the first study to start unravelling the relationship between foraging rates, parenting behavior, and stress-related hormone levels in the Bat-eared Fox.