Mustela itatsi Linnaeus 1758

45.

Japanese Weasel

Mustela itatsi

French: Putois du Japon / German: Japan-Wiesel / Spanish: Comadreja japonesa

Taxonomy. Mustela itatsi Temminck, 1844,

Japan.

The Japanese Weasel was previously considered a subspecies of the Siberian Weasel. Monotypic.

Distribution. Japan. Introduced to Hokkaido and Russia (S Sakhalin).

Descriptive notes. Head-body 28-39 cm (males), 25-30- 56 cm (females); tail 15- 5— 21 cm (males), 13: 3-16.4 cm (females); weight 660-820 g (males), 360-430 g (females), adult males are almost twice the weight of females. The Japanese 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.

Habitat. Forests. Often found in close proximity to water and sometimes near human dwellings.

Food and Feeding. The diet includes insects, reptiles, and small mammals. In Hamura, Japanese Weasels eat rodents, fish, arthropods, and crustaceans throughout the year; seasonal changes in the diet are small. In Tachikawa, the main food items are rodents and fruits in winter and spring, and arthropods and crustaceans in summer and autumn. On Zamami Island, where Japanese Weasels were introduced in 1957 and 1958, they eat a wide variety of prey, mainly insects, followed by reptiles and small mammals.

Activity patterns. Nocturnal.

Movements, Home range and Social organization. Solitary.

Breeding. Mating occurs in late winter and births occur in the spring.

Status and Conservation. Classified as Least Concern in The IUCN Red List. The Japanese Weasel is considered common throughout its range. This species has been introduced to certain areas to control reptiles and rats. Very little is known about Japanese Weasels and field studies are needed to learn more about their natural history, ecology, and conservation status.

Bibliography. Fujii et al. (1998), Keishi et al. (2002), Okada et al. (2007), Sekiguchi et al. (2002), Wozencraft (2005).