Female reproductive physiology in the aardvark (Orycteropus afer): A novel case report

There is scarce literature describing reproductive biology in the aardvark (Orycteropus afer). Although knowledge from species-specific endocrine monitoring can be applied to in situ and ex situ programs, endocrine profiles have yet to be described for this species, which experiences poor reproductive success in managed care. In this case report, we characterized aspects of aardvark reproductive physiology in a single female using longitudinal monitoring of hormones and behavior, description of physical characteristics, and ultrasonography during the estrous cycle, breeding, gestation, parturition, and lactation. Fecal progesterone (P4), total estrogens (E), and androstenedione (A4) concentrations were measured 2 – 4 times weekly by radioimmunoassay and paired with behavioral data to identify estrous cyclicity and gestation. The breeding pair was housed together from 337 to 232 days prior to parturition, with breeding observed via camera monitoring. Baseline P4 was 193.0 ± 126.68 ng/g (mean±SD) while pregnancy P4 levels rose to 18,939.8 ± 11,926.17 ng/g. Baseline E was 17.44 ± 11.86 ng/g and follicular phase peak E was 276.73 ± 100.06 ng/g. A4 was found to be uninformative in this study. Pregnancy was diagnosed by transabdominal ultrasound approximately 3 months into gestation and fetal development was monitored until parturition. Length of gestation was confirmed as previously reported (213 – 258 days), as we estimated the length to be 231 days. Furthermore, we described, for the first time, aardvark pregnancy diagnosis, nursing behavior, return to ovulation during lactation and estrous cycle length (19 ± 5.29 days). These data may help with management decisions and contribute to improving success of aardvark reproduction in managed care.