Onyono P N, Kavoi B M, Kiama S G, Makanya A N
Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. BOX 30197-00100, Nairobi, Kenya; Department of Veterinary Anatomy and Physiology, Egerton University, P.O. BOX 536-20115, Egerton, Kenya.
Department of Veterinary Anatomy and Physiology, University of Nairobi, P.O. BOX 30197-00100, Nairobi, Kenya.
Tissue Cell. 2017 Oct;49(5):612-621. doi: 10.1016/j.tice.2017.07.005. Epub 2017 Jul 28.
Optimal functioning of the olfactory system is critical for survival of fossorial rodents in their subterranean lifestyle. This study examines the structure of the olfactory mucosa and olfactory bulb of two fossorial rodents exhibiting distinct social behaviors, the East African root rat and the naked mole rat. The social naked mole rat displayed simpler ethmoturbinates consisting of dorsomedial and broad discoid/flaplike parts that projected rostrally from the ethmoid bone. In the solitary root rat however, the ethmoturbinates were highly complex and exhibited elaborate branching which greatly increased the olfactory surface area. In addition, when correlated with the whole brain, the volume of the olfactory bulbs was greater in the root rat (4.24×10) than in the naked mole rat (3.92×10). Results of this study suggest that the olfactory system of the root rat is better specialized than that of the naked mole rat indicating a higher level of dependence on this system since it leads a solitary life. The naked mole rat to the contrary may have compensated for its relatively inferior olfactory system by living in groups in a social system. These findings demonstrate that structure of the olfactory system of fossorial mammals is dictated by both behavior and habitat.
嗅觉系统的最佳功能对于穴居啮齿动物在其地下生活方式中的生存至关重要。本研究考察了两种表现出不同社会行为的穴居啮齿动物——东非根鼠和裸鼹鼠——的嗅黏膜和嗅球结构。群居的裸鼹鼠的筛鼻甲结构更简单，由从筛骨向前突出的背内侧和宽阔的盘状/片状部分组成。然而，独居的根鼠的筛鼻甲高度复杂，呈现出精细的分支，极大地增加了嗅觉表面积。此外，与整个大脑相关联时，根鼠的嗅球体积（4.24×10）大于裸鼹鼠（3.92×10）。本研究结果表明，根鼠的嗅觉系统比裸鼹鼠的嗅觉系统更具特异性，这表明由于根鼠过着独居生活，它对该系统的依赖程度更高。相反，裸鼹鼠可能通过在社会系统中群居来弥补其相对较差的嗅觉系统。这些发现表明，穴居哺乳动物嗅觉系统的结构受行为和栖息地两者的支配。
