Using odors underground

Subterranean rodents that have adapted to living primarily underground have conquered numerous sensory and behavioral challenges that the harsh, though relatively secure, subterranean habitat presents (see reviews of Nevo 1999; Bennett and Faulkes 2000; Lacey et al. 2000). The advantages of colonizing the subterranean niche, primarily environmental stability and safety from predation, may seem trivial, however, in light of the disadvantages. Life-sustaining food can only be acquired by digging through solid soil. In the darkness of the subterranean tunnel territories, surrounded by earth, the sensory information necessary for locating food and mates is highly constrained. Edible plants may be widely scattered and prospective partners are dispersed somewhere in neighboring tunnel territories. In contrast to surface dwellers, subterranean rodents cannot see plants or other animals either close-up or far away nor can they smell plants or other animals froma distance. In contrast to the sensory adaptations made in the visual, auditory, and somatosensory systems of subterranean rodents (Nevo 1999), the olfactory system, such as in blind mole rats (Zuri et al. 1998), functions similarly to that of other rodents despite the different context. This chapter summarizes recent studies that shed light on and extend the limited knowledge about olfaction in subterranean rodents. These studies demonstrate that olfaction plays an important role not only in finding food but also in social interaction, especially recognizing familiar individuals and choosing mates. There is also evidence that urine and body odors of subterranean rodents provide individually distinctive chemosensory cues that are also indicative of the individual's sex, population, and species, and that subterranean rodents respond to the similarities and differences between odors of conspecifics and heterospecifics. Although the availability of suitablematesmay be restricted underground, subterranean rodents, given the opportunity, prefer the odors of (and to mate with) genetically dissimilar individuals, i.e., non-kin as opposed to kin. The odor-based processes enabling individual recognition and differential responses based on genetic relatedness in subterranean rodents are a particular focus of this chapter.