Abstract: The population ecology of ground squirrel(Spermophilus dauricus)were studied from1987- 1989．A total of 2487 specimems(Female 1334， Male 1153)obtained in Quwo,Fenyangcounty，Shanxi Province and Yanchang，Heyang County，Shanxi Province．Withthe dried 1ens weight as a criteria， 1885 specimens of them were divided into 5 groups.The dried lens weight of group 1(Juvenile)was≤ 18 mg in both sex； group 2(Subadult)18.01-23 mg in female and 18.01-22 mg in male;group 3(Adult 1)23.01- 29mgin female and 22.01- 28 mg in male；group 4(Adult 2)29.01- 35 mg in female and28.01-34 mg in male;group 5(Older)>35 mg in fomale and>34 mg in male．Weinvestigated the dental growth and it's weardegree in different age groups and analysed the relationships between body weight，body length,body weight without viscera，skull growth and ages． The reaults showed that the regularity of molar wearing withage growing was obvious while the other age indicators growed very slowly afteradult 1．According to the dried lens weight of age groups，weestimated the naturallongevity of ground squirrel was about 4 years．
The seasonal variations of the population age structure were obvious． Group 1began to appear in late June in Quwo，Heyang area and in early July in Fenyang，Yanchang． The proportion of group 1 was the highest in July in the four areas． The individuals of group 2 increaed rapidly while group 1 descended in August． The proportion of group 3 was higher than the other age groups during September to June ofthe next year． The individuals of gronp 4 increased from April and continued to June．Group 5 was low in number in all months． The annual changes of the population agestructure werenot marked．Generally，the proportion of nonadults was high while oldors was low，it showed the population of ground squirrel in quantity was relativelystable．

Key words: Ground squirrel(Spermophilua dauricua )l Dried lense weight}Population age structure

摘要： 1987-1989年，作者捕获达乌尔黄鼠2 487只，用晶体干重法，将其中的1 885只划分为5个年龄组，分析不同年龄阶段臼齿的生长、更换、磨损特点以及体重、体长、 胴体重及头骨生长的年龄变化。结果表明随着年龄增长，臼齿磨损明显，而体重、体长等5项指标趋于恒定。达乌尔黄鼠种群年龄结构的季节变化非常显著，不同地区间亦有差别，但年间变动较小，种群增长比较稳定。

关键词: 达乌尔黄鼠, 晶体干重, 种群年龄结构