引言鼠类属哺乳动物中的啮齿类。种类繁多、数量大、分布广、与人类关系密切。其中有许多种类对人类危害很大。鼠类和其它啮齿动物具有下列二点特征:(1)有齿虚位,即在门齿和颊齿之间无犬齿,而有一较长空隙,这个空隙就叫齿虚位或齿隙。(2)门齿很发达,无齿根,故能终生生长。如不给它经常啃啮东西,特别是咬较硬的东西,上下 Introduction Rodents are mammalian rodents. A wide range of large quantities, widely distributed, and human beings are closely related. Many of these species are very harmful to humans. Rodents and other rodents have the following two characteristics: (1) toothed phantom, that is, between the incisors and cheek teeth without canines, and there is a long gap, the gap is called tooth phantom or backlash. (2) incisor is very developed, no tooth root, it can grow for life. If you do not give it regular nibbling things, especially biting harder things, up and down