Myosorex varius

434. South African Mouse Shrew Myosorex varius French: Musaraigne sud-africaine / German: Sldafrika-Mausspitzmaus / Spanish: Musarana ratén de Suréfrica Other common names: Forest Shrew Taxonomy. Sorex varius Smuts, 1832, Algoa Bay, Cape of Good Hope (= Port Elizabeth, Eastern Cape Province, South Africa). Seems to form a clade with M. meesteri, M. slateri, M. cafer, and M. tenuis. The Limpopo population of M. tenuis is imbedded within this species orsister to it, indicating that M. varius may be a species complex. Monotypic. Distribution. South Africa, Lesotho, and W Swaziland. Descriptive notes. Head-body 76-88 mm, tail 38-48 mm, ear 6—11 mm, hindfoot 14-16 mm; weight 6-11 g. The South African Mouse Shrew is a medium-sized shrew. Individuals from higher altitudes in the Drakensberg Mountains are much smaller than typical individuals of this species from lower altitudes. Dorsal pelage is mottled gray brown to dark gray brown, the hairs being slaty gray basally, with an off-white subterminal band and a dark brown tip; ventral pelage is pale gray, occasionally with a yellowish tinge, the hairs being slaty gray at base, with a white to fawn tip. Feet are pale gray. Tail is of medium length (c.50% of head-body length), covered in sparse hairs throughout, and bicolored, pale to dark brown above, fawn to white on the sides and below. Females have six inguinal nipples. There are four unicuspids. Habitat. Found primarily in dense, moist savanna and grassland habitats; also recorded from forests and drier areas in Karoo National Park in South Africa, where mist provides moist microhabitats for the species. The South African Mouse Shrew occurs at elevations from sea level up to ¢.3000 m. Food and Feeding. The South African Mouse Shrew feeds on a variety of invertebrates, primarily arthropods. Stomach samples from Drakensberg Mountains indicate that they feed on adult coleopterans (58% frequency of occurrence), hymenopterans (53%), orthopterans (24%), larval lepidopterans (22%), larval coleopterans (20%), arachnids (20%), blattoideans (16%), hemipterans (11%), as well as less than 10% frequency of six other insect orders. In captivity, individuals feed readily on earthworms, locusts, grasshoppers, bagworms, termites, and beetles. On occasion, South African Mouse Shrews will consume small amounts of plant matter. They seem to be occasionally cannibalistic and probably scavenge carrion, as do other shrews; refection has also been observed. Breeding. Reproductive activity occurs largely in the wet season or whenever there is significant rainfall in the ecosystem. This varies geographically, however, and some populations in the Western Cape breed all year round, with most pregnancies occurring from June to September. In most locations though, breeding occurs from August, September or October to February-April. During courtship, the male persistently chases the female until she stops and allows him to mount. Embryo count is 1-6 throughout much of the range but averages within the range of 2-5-3-8 embryos. When born, young are blind, naked, and helpless but development is very rapid; young cling to the nipple from birth to day 5 or 6, and caravan until they are weaned, which is at about day 20-24. The South African Mouse Shrew lives 12-16 months, generally with a massive die off of the older adults toward the end of the breeding season. In the dry season, populations consist of subadults (50-60%) and adults (30%) with very few older individuals, while by the midto late wet season, populations consist of juveniles (20%), subadults (40%), and adults (40%). In captivity, individuals can survive significantly longer, up to 2-5 years. Activity patterns. South African Mouse Shrews are terrestrial and largely nocturnal, although they become predominantly diurnal in the dry season, completely changing their circadian rhythm to conserve energy. During the dry season, they will rest in well insulated nests during the coldest hours of the night. They burrow actively to find food and probably build burrows. Movements, Home range and Social organization. South African Mouse Shrews are fairly aggressive and become more so at the beginning of the breeding season, being known to attack and even kill one another. Males and females maintain territories during the wet and dry seasons, ranging from 0-08 ha to 0-2 ha; male and female territories generally overlap. Territories are marked using secretions from their chin and lateral glands, as well as strongly scented fecal piles around the borders. A strong odor is also exuded when they are alarmed, and this can be smelt by humans from several meters away. Vocalizations include short, sharp squeaks when alarmed and during aggressive encounters, squeaks frequently interspersed with drawn out chirrs; chittering can also be heard between male and female partners and between mother and young. Status and Conservation. Classified as Least Concern on The IUCN Red List. The South African Mouse Shrew is common and widespread, and is the best-studied species in the genus. Lead-poisoning, exacerbated through biomagnification, may be a threat to the species. Bibliography. Baxter (2005), Baxter & Dippenaar (2013g), Baxter & Lloyd (1980), Baxter et al. (1979b), Cassola (2016bf), Lynch (1994), Reinecke et al. (2000), Rowe-Rowe & Lowry (1982), Rowe-Rowe & Meester (1982), Taylor et al. (2013), Willows-Munro & Matthee (2011b).Published as part of Russell A. Mittermeier & Don E. Wilson, 2018, Soricidae, pp. 332-551 in Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona :Lynx Edicions on pages 547-548, DOI: 10.5281/zenodo.687084