关键词: 黄胸鼠, 形态, 栖息, 繁殖, 种群, 长江流域, 洞庭湖区

Abstract: The evidence indicated that the Buff-breasted rat that distributed mainly in south China and Southeast Asia is spreading to the north. Although the population density of the animal in south China is still higher than that of in north China, the population of this animal is increasing in the north China and decreasing in south China. It is suggested that the worming climate be one of the most important reasons for the spreading of the animal and the increasing of the population in north. The population of the animal decreasing in south is because of the improving of house structure.
The rats in south China inhabit both in farmer’s house and on farmland. However，the rats distributing in north China mainly inhabit in the buildings. These perhaps relate to the differences of climate between the north and the south.
The mean body weight，body length and tail length are 86.7g，142.9 mm and 157.6 mm respectively in Dongting Lake region. The body length of the animals in Dongting Lake region is generally shorter than the tail length. However, the proportion of the individuals that the tail length is shorter than the body length in Dongting Lake region is lower than that in Yunnan.
The animals breed all the year in Dongting Lake region. The breeding potential of the animal reaches the peak during April and May. The monthly mean value of rate of pregnancy and index of reproduction (litter size number of subadult + adult females) are 25. 5% and 1 .99 respectively. The mean litter size is 7. 11(range 1-17) . The monthly mean proportion of testes in scrotum is 68.0%. The animals that distribute in north China stop breeding in winter.

Key words: Buff-breasted rat (Rattus flavipectus), Morphology, Habitat, Reproduction, Population, Yangtse valley, Dongting Lake region