Abstract: The animal gut morphology is closed related to foo habit,food quality and energy need．The seasonal changes in length and weight of total and separate organs of digestive tract in root vole (Microtus oeconomus)，which lived in Qinghai-Tihetan plateau，was determined．It was showed that the length，weight of with content,empty and dry tissues of total and every organs (stomach，small intestine,large intestine and caecum )of root vole gut had significant seasonal variations．Each index was the lowest in exeuheranee period，which is moderate to vole，while in green up and／or whithering period，which the fiber content is high in food and-temperature is low ，all indexes were higher．The responsive magnitude of each organ was different and the small intestine responded strongly to the seasonal acclimatization．This suggested that the adjustment in morphology and capacity of digestive tract is important in animals digestive strategies．Diferent organs showed diferent responses to different stress，similarly，different pressure have a different effeet to the digestive tract．0ur results indicated that root vole have the ability physiologically to adapt the high-fiber food and lowtemperature environment in their natural habitats．

Key words: Microtus oeconomus, Gut morphology, Nutrition, Adaptive strategies

摘要： 动物消化道的形志与食性，食物质量以及动物对能量的需求密切相关。本文对青海高原地区的根田鼠(Microtus oeconomus)在自然环境中消化道各器官的长度及重量进行了测定，结果显示总消化道及各嚣官(胃、小肠、大肠和盲肠)的长度，含内容物重(鲜重和干重)在各物侯期间具显著的变化，各项指标均于环境条件较好的植物生长盛期最低，于条件较差(食物纤维素含量高及低温)的植物枯黄期或返青期较高。各器官所反应程度不同，其中小肠的反应最为强烈，表明消化道形态及容量的调节是消化对策中的一个重要方面，根田鼠在生理上有能力适应高纤维素食物和低温环境。

关键词: 根田鼠, 消化道, 营养, 适应对策