Monitoring the gestation period of rescued Formosan pangolin (Manis pentadactyla pentadactyla) with progesterone radioimmunoassay

Abstract

Eight species of pangolin have been identified in the world. However, understanding of pangolin reproductive biology has been limited to fragmentary records. In this study, the concentration of serum progesterone in three pregnant and two nonpregnant rescued female Formosan pangolins (Manis pentadactyla pentadactyla) was monitored using a commercial progesterone radioimmunoassay kit. During gestation, the serum progesterone of pregnant pangolins A, B, and C remained at 28.5-55 ng/ml (n = 31 samples), 10.9-50.1 ng/ml (n = 34), and 12.4 and 33.5 ng/ml with a peak at 47.6 ng/ml (n = 19), respectively, whereas the serum progesterone of nonpregnant pangolins D and E remained at 1.99 ± 1.62 ng/ml (n = 80) and 2.27 ± 1.64 ng/ml (n = 27), respectively. From this study, it was found that female pangolin weighing as low as 2.14 kg was already capable of reproduction. For pregnant pangolins to give birth to viable offspring, their body weight must increase significantly, 63.89 and 134.0% in the study, from the time of inception or early pregnancy until parturition. In addition, study has found that both viable offspring were born fully developed and exceeded 80 g in weight. The period of gestation was found to be as short as 318 or longer than 372 days. Therefore, the Formosan pangolin should only be able to reproduce once a year. This study is the first insight into hormone assay for determining the gestation period of pangolin. Further investigations on the same subject are necessary to establish criteria for the recognition of reproductive status in pangolins.

Feeding Asian pangolins: An assessment of current diets fed in institutions worldwide

“…Diets which contained a higher amount of chitin may have increased apparent organic matter digestibility due to the larger food mean retention time associated with more chitinous diets (Lin, Chang, Yang, & Dierenfeld, ). A similar observation made with soil addition by Chin et al (). This may help the nutritional management of rescued pangolins which require critical care and a sustained nutrient intake, assuming they find the diet palatable.…”

Reproductive behavior of the captive Sunda pangolin (Manis javanica Desmarest, 1822)

“…In addition, a male with strong sexual desire can mate with multiple females, suggesting that Sunda pangolins may not be very selective about their mates. In captivity, Chinese pangolins (Chin et al, ; Yang et al, ; Zhang et al, ), Indian pangolins (Mohapatra et al, ), and Cape pangolins (van Ee, ) can also be successfully paired with one individual.…”

Captive breeding of pangolins: current status, problems and future prospects

“…So, the reproduction parameters of pangolins are quite inaccurate. At present only few reproductive traits, including pangolin’s time of birth, estrus, gestation period and litter size were reported (Chin et al 2011). …”

“…Different species of pangolin have different gestation periods, Cape Pangolin’s gestation period is about 139 days (van Ee 1966), the gestation periods of the Tree Pangolin and Long-tail Pangolin are close to the Cape Pangolin’s; the Indian Pangolin’s gestation period is shorter, just 65–70 days (Hayssen and Van Tienhoven 1993). The pregnancy period of the Chinese Pangolin is about 101–169 days (Wu 1998b; Yang et al 2007), but by monitoring the concentration of the serum progesterone, Chin et al believed that the gestation period of the Chinese Pangolin was 318 to 372 days (Chin et al 2011), which is significantly different from the results of Wu’s and Yang’s observations (Wu 1998b; Yang et al 2007), suggesting that more systematic and quantitative analysis are needed to determine pangolin’s reproduction parameters. Pangolins are believed to give birth to one young each time, but twins are known (Lim 2008a).…”