Reproductive Ecology and Human-Caused Mortality in the Japanese Mamushi Snake (Gloydius blomhoffii) on the Northernmost Main Island of Japan

Abstract

Abstract Japanese Mamushi (Gloydius blomhoffii) has long been exploited for its medicinal value. We studied this snake's reproductive ecology on Hokkaido and assessed its vulnerability. We marked 299 individuals from 1999–2002 and kept 29 pregnant females in captivity until parturition. Pregnant females aggregated at gestation sites during summer and fall until just before parturition. Behavior suggestive of mating seasons was evident mostly in August and September. As expected, there was an apparent sex difference in body size in adults but not in neonates: females were larger than males. Consistent with previous reports, both neonates and adults were larger in Hokkaido than in southern Japan. The smallest pregnant female measured 44.8 cm in SVL, which was larger than values reported from southern regions. Offspring sex ratio was statistically equal: 88 males to 105 females. Litter size averaged 6.6 offspring. Longer females tended to produce larger litters and longer neonates. The proportion of pregnant...