Diets and habitat preferences of three species of crocidurine shrews in arid southern Africa



The diets and habitat preferences of three species of crocidurine shrews, Crocidura cyanea, C. fuscomurina, and C. hirta (Insectivora: Soricidae), were studied in arid areas of Namibia in March and April, 1992. Simultaneous sampling of the prey ingested and available along foraging trails showed that, although the shrews are generalist insectivores that take most types of prey from the range available, each species selected Araneida, Chilopoda, Isoptera, and insect larvae but avoided Formicidae. The preferred prey were mostly soft-bodied with a relatively high ratio of body water to energy content, which may assist in maintenance of body water balance. The three species showed inconsistent preferences for rarer categories of prey such as Thysanura and Orthoptera, as well as for Coleoptera. Each species of shrew selected sites providing dense ground level vegetation and deep leaf litter, With the preference for cover being strongest in C. fuscomurina. Dense vegetation probably provides shelter from predators and high daytime temperatures; both C. fuscomurina and C. hirta used denser vegetation by day than by night. Each species foraged in leaf litter, perhaps increasing access to preferred types of prey. Preference for moist soil, especially in C. fuscomurina, probably also reflects increased access to preferred prey, although moist soil may also facilitate burrow construction. Because patterns of habitat and diet selection appear to be linked, future research on resource use in these shrews should be pursued most fruitfully in field experiments or captive laboratory trials.