アカネズミの齢推定法
1980 年 30 巻 2 号 p. 109-116
詳細
1980 年 30 巻 2 号 p. 109-116
The population of the Japanese wood mouse at Mt.Daimonji, Kyoto, had two distinct birth seasons in spring and autumm and its members included individuals of 4 or 5 half-year age classes. Nine stages of wearing were distinguished by the pattern of the occlusal surface of the upper first, second, and third molars. In the course of the population studies from 1965 to 1971,118 specimens were obtained and classified into 4-5 groups with similar type of tooth wear, each of which would correspond to each of successive birth season. Accuracy of this estimation was certified by examining the 23 specimens of known age that were obtained by the capture-recapture method. The wearing of tooth was more rapid in winter than in summer, but the difference was small enough to determine their birth season. Various methods of estimating age hitherto proposed for this species were tested using the present specimens. The results indicated that the present method was most accurate and valid.
