Muridae Author Don E. Wilson Author Russell A. Mittermeier Author Thomas E. Lacher, Jr text 2017 2017-11-30 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 7 Rodents II 536 884 book chapter http://doi.org/10.5281/zenodo.6887260 a016af63-6437-427b-80b7-22bc9a002e20 978-84-16728-04-6 6887260 420. Nairobi Grass Rat Arvicanthis nairobae French: Rat-roussard de Nairobi / German: Nairobi-Grasratte / Spanish: Rata de hierba de Nairobi Other common names: East African Arvicanthis Taxonomy. Arvicanthis nairobae J. A. Allen, 1909 , Nairobi, Kenya. Arvicanthis nairobae is easily confused with A. mniloticus, making the geographical boundaries of the species unclear. Diagno- sis is best based on chromosomal comple- ment, that of nairobae having 2n = 62, FN = 78. Monotypic. Distribution. On basis of chromosomally determined specimens, Nairobi Grass Rat occurs in narrow band from C & W Kenya to N Tanzania; it may be present also in S Ethiopia. Descriptive notes. Head—body 118-167 mm, tail 94-129 mm, ear 15-19 mm, hindfoot 22-30 mm; weight 51-135 g. The Nairobi Grass Rat is medium-sized; fur dorsally quite coarse and grizzled chestnut brown, and ventrally tan and softer-textured. Ears are small and covered with short brown hairs. Tail is relatively short (¢.73% of head—body length), darker above than below, and coarsely scaled with small bristles. Limbs are relatively short, with four digits on forefoot (first digit is absent; fifth digit is highly reduced but still bears a claw) and five digits on hindfoot. Habitat. Somali-Masai grasslands and savannas, especially where there is woody cover combined with long grasses; e.g. dead trees and man-made bomas (livestock enclosures comprising woody Acacia fence). Food and Feeding. The Nairobi Grass Ratis herbivorous. Dietmostly consists of grass, with other plants; some arthropods also eaten. Breeding. Reproduction is seasonal. Average litter size (number of embryos) 5-5 (range 2-12). Activity patterns. Nairobi Grass Rats are diurnal and terrestrial. Movements, Home range and Social organization. The Nairobi Grass Rat is very social, living in large colonies. Densities may reach 100-200 ind/ha. Status and Conservation. Classified as Least Concern on The IUCN Red Lust. Bibliography. Castiglia et al. (2006), Happold (2013a), Monadjem et al. (2015), Neal (1981).