Abstract:Wild populations of the five-paced pit-viper (Deinagkistrodon acutus) are increasingly threatened due to overhunting by local human populations, who kill the snakes mostly for food and medicinal use, and to a lesser extent for their skin to use in handiwork. Because D. acutus is currently classified as a highly vulnerable species in China, there is increased urgency to develop artificial breeding technology to ensure the long-term survival of the species. Although a number of farms currently breed D. acutus under semi-basement captive conditions, the artificial breeding technology for this species is still in its infancy, and few studies have empirically investigated the reproductive characteristics of D. acutus. In order to increase our understanding of the reproduction of D. acutus, and hence improve prospects of artificially breeding the species, we studied the body size, clutch size, clutch mass and other reproductive characteristics of adults under semi-basement captive conditions in Yongzhou City of Hunan Province from April-September 2010. We collected 42 healthy D. acutus (14♂28♀) adults and housed them in semi-basement conditions within Yongzhou YISHE Technology Co., Ltd. The snakes' housing consisted of seven cement pools (1.5 m length, 1.0 m width, 1.2 m height), which each had a 20 cm-thick layer of soil on the bottom and a nylon net covering the top. Six individuals (2♂4♀) were put into each pool, in which the temperature was 16-29℃ and relative humidity was 78%-96%, and housed from April 15-September 15. Because D. acutus are typical sit-and-wait foragers, adults were fed on house mice (Mus musculus), domestic ducks and chickens. Captive D. acutus mainly preyed on live, small animals during the pre-breeding period, predating on live mice, live ducklings and live chicks in decreasing order. Oviposition season was from 2-21 August, and during this time we measured female body weight after oviposition (postpartum mass), snout-vent length (SVL), tail length (TL), oviposition time, clutch size, clutch mass, egg mass, egg length, egg width and relative clutch mass (RCM). All adult females laid a single clutch (mean egg number=23.0±7.8; (13-37); n=23) during the breeding season and maintained a larger nest egg output. Clutches were made up of eggs with flexible shells and females displayed parental care behaviors to protect them. Clutch size, clutch mass and egg mass were positively correlated with female prenatal mass, but not with female size (SVL) (using SPSS 13.0 to process data with significance level α=0.05 and α=0.01, and taking the sum of both the postpartum mass and the clutch mass as the prenatal mass). Egg mass was positively correlated with egg width and egg length, but not with clutch size. From our analysis, we show that females with prenatal mass of 1000-1200g produced clutches of eggs that were more numerous and heavier, which in turn guaranteed the survival of the resulting offspring. We suggest that female prenatal mass could be a criterion used in artificial breeding programs for D. acutus, and selecting females with prenatal mass of 1000-1200g could help produce greater numbers of healthy young in semi-basement farms that are seeking to breed the species.