In this study,the social ranks of male root vole siblings ( Microtus oeconomus
) were determined by dyadic interaction test,and then their behavioral patterns to orders of fresh urine from familiar and novel male voles were investigated in a behavioral choice maze. The behavioral statistics showed that: 1. The urine marks can be used as the standard to estimate social rank when two voles in dyadic interaction. 2. Subordinates preferred familiar odors. They spent more time visiting and approached more frequently to familiar odors than strange ones. And they self-groomed much more in familiar odorant box than in strange one. 3. Dominants preferred strange odors, and showed significant differences between the familiar odors and the strange odors in visit time, sniff/lick frequency and time, self-grooming, and countermarks. 4. There existed a significant difference in behavioral pattern of response to strange odors between the dominant and subordinate voles. The results indicate that different response patterns of male voles in different social ranks reflect the different territorial behavioral patterns.