Physiological and ecological investigation of mouse deer and their conservation in Malaysia.

鼠鹿是现存最小的反刍动物，它们在白天而不是夜间活动，尽管它们被认为是夜行动物。大鼠鹿和小鼠鹿分布于东南亚。它们的栖息地通常是隔离的，但在某些地区，两个物种共享它们的栖息地。染色体分析表明，尽管大小鼠鹿都有32条染色体，但它们的区别在于Y染色体短臂的不同。鼠鹿的rRNA基因仅限于性染色体上，不像其他哺乳动物一般在常染色体上有rRNA基因。头骨形态的区域差异将小鼠鹿分为老挝、马来半岛、兰卡威群岛和苏门答腊4个类群。咀嚼肌表明，鼠鹿适应吃软叶（浏览器），而不是吃草（放牧）。主动脉弓的动脉分支模式是偶蹄目动物的特征，没有反刍动物的特征性奇异网。红细胞在哺乳动物中最小的红细胞中有一个独特的小坑。小窝在小红细胞中占据相对较大的空间。胎盘也不同于其它反刍动物的胎盘，睾丸间质细胞内有特殊的丝状纤维束。目前对小鼠鹿和大鼠鹿的研究揭示了这些小生物的一些有趣和新颖的特征。

The mouse deer, the smallest living ruminants, were active during daytime rather than nighttime, though they have been believed to be nocturnal animals. Two kinds of muse deer, lesser and greater mouse deer, distribute in Southeast Asia. Their habitats are usually segregated, but in some areas both species shared their habitats. From chromosome analysis, lesser and greater mouse deer were discriminated by the difference of the short arm of Y chromosome, though both have same 32 chromosomes. The rRNA genes were restricted in sex chromosome in mouse deer, unlike other mammals having rRNA at the autosomes generally. Regional variations of skull morphology segregated 4 groups from Laos, Malay Peninsula, Langkawi islands and Sumatra in lesser mouse deer. Mastication muscles indicated the mouse deer adapt to eat soft leaf (browser) rather than grass eating (grazer). The arterial branching pattern from the aortic arch is characteristic among artiodactyla, and there is no rete mirabile epidurale, which is characteristic of ruminants. The erythrocytes had an unique pit in the smallest erythrocytes among mammals. The pit occupied relatively large space in the small erythrocytes. The placenta also differedfrom those of other ruminants, and peculiar filamentous bundles were observed in the Leydig cells of testes. The present study on the lesser and greater mouse deer revealed several interesting and novel characteristics in these small creatures.