Based on population surveys of great gerbil(Rhombomys opimus)by blocking up the mouseholes and inspecting the opened ones conducted in three different habitats in Tengenor,Damaolianheqi,Baotou City of Inner Mongolia in February,April,June,August,October and December from 2003 to 2005,relationship between density of the great gerbil and rainfall was analyzed.Results showed that population densities of the great gerbil vary with seasons and years,and its density curves have a single peak value every year.A regression equation Y8=-8.7202 + 0.8806X(df=16,r=0.5394>r0.05=0.468)resulted from analyzing the relationship of the density to the rainfall the previous month indicates that the population size of the great gerbil was positively related to the previous month’s rainfall.The density occurring in August and October can be predicted by that in April.The forecasting models for the density in August and October are Y8=-1.0925+2.6133X4(df=6,r=0.9776>r0.01=0.834)and Y10=-0.2097+2.4992X4(df=6,r=0.9672>r0.01=0.834)respectively.
