Siberian Weasel

The Siberian weasel is a long, slender weasel on short legs, with a narrow head, short broad-based ears and a fluffy tail about half the body length. The coat is bright reddish-ochre or straw-red, with a dark coffee-brown facial mask and white lips and chin, and winter fur is dense and soft. Males measure 28 to 39cm and weigh 650 to 820g, and females are smaller at 25 to 30.5cm and 360 to 430g. The Himalayan form, subhemachalana, is smaller than the nominate form and has a blackish tail tip (Wikipedia, general species account).

It hunts actively, chasing prey through snow, water and buildings, and eats about 100 to 120g a day, caching surplus food. It nests in fallen logs, stumps, brush piles and tree roots, sometimes taking over other animals' dens. Mating is in late winter or spring, gestation lasts 38 to 41 days, and litters of 4 to 10 blind kits become independent by late summer. The source lists Bhutan in the range but gives no Bhutan-specific detail; the entry in this guide is under the scientific name Mustela horsfieldii, the Himalayan weasel, which the source treats as part of this species (Wikipedia, general species account).