Growth Pattern in the Juvenile Japanese Grass Snake, Rhabdophis tigrinus tigrinus, in Captivity

Abstract

Twenty-seven newborn Japanese grass snakes were reared for two years and four months in captivity at room temperature. Nine snakes each were fed every second day (Group A), fourth day (Group B) and sixth day (Group C). By the fourth week, all snakes belonging to Group A had grown larger in both snout to vent length and body weight than those belonging to Group B, whereas Group B had exceeded Group C only in body weight. On the contrary, condition index, calculated with the formula: body weight /(snout to vent length)3, was larger in Group B than in Group A after the age of one year. All snakes exhibited specific seasonal changes in growth pattern; body weight increased rapidly just before and after winter, whereas snout to vent length increased at a constant rate during these months. There was no apparent difference in seasonal changes of growth pattern among the three groups. Sexual dimorphism in tail ratio became distinct when snakes reached 290 mm in total length.