アカネズミ2種の齢査定

抄録

A method of determing age is proposed for Apodemus speciosus ainu and A. giliacus. In both species 6 relative age classes were created according to wear of the grinding surface of the upper third molar. Based on tooth wear of known-age individuals, pelage color or annual layers on the cementum of molars, approximate chronological age was estimated for each age class as follows : class 1-1 month old, class 2-1 to 2 months old, class 3-2 to 3 months old, class 4-3 to 10 months old and classes 5 and 6-more than 10 months old. The method proposed was compared with those described by previous workers and applied to the trappable populations from different areas of Hokkaido. In both species the current year's mice first appeared in June and made up a large portion of the populations from July.