STUDY ON THE POPULATION AGE-STRUCTURE OF THE GREATER LONG-TAILED HAMSTERS IN BEIJING-TIANJIN AREA

The author studied the population ecology of the greater long-tailed hamsters from April, 1983 to June, 1985 in Beijing-Tianjin area.A total of 989 speciemens were obtained, among which 508 were males and 481 females.This paper reports the following results of the study on the population age-structure. 1. With the body weight excluding all the viscera as a major index,speciemens were divided into four age groups, Group I . Juvenile : The weight was≤40g. Group Ⅱ .Subadult:The weight was 40. 1-75g. GroupⅢAdult( 1 ):The weight was 75. 1 -120g. GroupⅣ.Adult(2 )sThe weight was120g. This division of age groups is relatively accurate and easy to practice. 2. The population size of different age groups varies with different seasons. Two peaks of juveniles' quantity occured in May and Aug.For the subadults it occured in Aug. -Sep. ,adult( 1 )in Oct. ,adult(2 ) in this Oct. - next Apr.. 3. The total sex ratio is , and the sex radio between to increases with the age of Gricetulus triton.