Abstract: The purpose of this study was to investigate the differences in limb bones of rodents with different living habits,in Mudanjiang City of Heilongjiang Province. The limb bone strength, weight percentage and dynamic arm coefficient of Apodemus peninsulae and Myodes rufocanus in forest ecosystem, Microtus fortis and Apodemus agrarius in farmland ecosystem were measured and calculated. Results showed that the average values of ulnar, radius and femur of Microtus fortis, the average value of humerus of Myodes rufocanus and the average values of tibia and fibula of Apodemus agrarius were higher than the corresponding bones of the other three species. In the weight percentage of limb bone, the proportion of hind limb bone was larger than that of forelimb bone in two habitats, which was in line with the optimization design principle of limb bone of mice that were good at running and jumping in forestry and agricultural areas. The dynamic arm coefficient showed that the burrowing rodents, Microtus fortis and Apodemus agrarius, had stronger digging ability than the ground dwelling rodents,such as Myodes rufocanus and Apodemus peninsulae, which reflected the adaptive changes of rodents to different skeletons of habitats and habits.

Key words: rodents, limb bone, stout degree, weight percent, Mudanjiang City