Mustela sibirica Pallas 1773

53. Siberian Weasel Mustela sibirica French: Putois de Sibérie / German: Sibirisches Feuerwiesel / Spanish: Comadreja siberiana Taxonomy. Mustela sibirica Pallas, 1773, Russia. Up to twenty-two subspecies have been proposed, but a taxonomic revision 1s needed. Distribution. Bhutan, China, India, Japan (Hokkaido), North and South Korea, Nepal, Laos, Mongolia, N Myanmar, Russia, Taiwan, and N Thailand. Introduced to several Japanese islands (Honshu, Kyushu & Shikoku Is). Descriptive notes. Head-body 28-39 cm (males), 25-30.5 cm (females), tail 15.5-21 cm (males), 13.3-16.4 cm (females); weight 650-820 g (males), 360-430 g (females), adult males are almost twice the size of females. The Siberian Weasel has a long, slender body and short limbs. The pelage is dark brown in summer and becomes paler, almost yellowish-brown in winter. The upper lips and chin are white. There is usually a dark mask around and in front of the eyes. The tail is about 50% of the head and body length, and may have a dark tip. There are four pairs of mammae. The skull is long and narrow. Dental formula: 13/3, C1/1,P3/3,M 1/2 = 34. Habitat. Siberian Weasels are found in forests, forest steppe, and mountains, from 1500 to 5000 m. They are often found in river valleys, near swamps, and in areas with dense ground vegetation, around villages, and in cultivated areas. Food and Feeding. The diet is mainly small mammals (rodents, pikas), but may also include amphibians, birds, eggs,fish, invertebrates, berries, and nuts. Siberian Weasels search for prey by exploring hollow trees, logs,cavities, brush piles, and other enclosed spaces. Activity patterns. Mainly nocturnal and crepuscular. Den/rest sites are under roots, in logs or tree hollows, modified rodent burrows, rock crevices, or buildings. Movements, Home range and Social organization. Siberian Weasels are solitary and terrestrial, but can climb and swim well. Nightly movements may reach 8 km. There are reports of Siberian Weasels relocating to new areas if food becomes scarce locally. Breeding. Mating occursin late winter and early spring. The gestation period is 33-37 days. The young are born in April to June, inside hollow trees, cavities among rocks or stumps,inside buildings, or in a modified rodent burrow; the nest is lined with fur and feathers from prey killed by the mother. The litter size is 2-12, usually five or six. The young open their eyesafter one month, and lactation lasts two months. They leave their mother by the end of August. Status and Conservation. Classified as Least Concern in The IUCN Red List. The Siberian Weasel is important in the fur trade. It occasionally attacks domestic fowl, but is generally considered beneficial because it preys on rodents. Little is known about Siberian Weasels and field studies are needed to learn more about their natural history, ecology, and conservation status. Bibliography. Francis (2008), Lekagul & McNeely (1991), Pocock (1941a), Rhim & Lee (2007), Sasaki & Ono (1994), Stroganov (1969), Wozencraft (2005, 2008), Wu (1999).Published as part of Don E. Wilson & Russell A. Mittermeier, 2009, Mustelidae, pp. 564-656 in Handbook of the Mammals of the World – Volume 1 Carnivores, Barcelona :Lynx Edicions on page 654, DOI: 10.5281/zenodo.571404