Burrows The Siberian weasel builds its nest inside fallen logs, empty stumps, brushwood piles and exposed tree roots. It also uses and enlarges the dens of other species. The length of its burrows ranges from and deep. Adults have a permanent burrow and up to five temporary shelters, which may be separated from each other by several kilometres. They build a nesting chamber in the middle or end of the burrow and line it with bird feathers and rodent hair.
Diet In terms of prey selection, Siberian weasels are midway between small,
rodent-eating
mustelids such as
polecats and the more polyphagous
martens. They rarely eat
reptiles,
invertebrates and
plants, preferring instead to prey on rodents of small to moderate size.
Water voles are their most frequent prey in their western range, while
voles and
mice are eaten in their eastern range. Moderate sized rodents targeted by Siberian weasels in the east include
Daurian and
Alpine pikas, and
Siberian zokors. In local areas,
chipmunks,
muskrats,
red squirrels and
jerboas are eaten.
Fish may be eaten in some areas during certain seasons. In
Ussuriland, they scavenge extensively on the kills of
wolves and
yellow-throated martens during the winter. Elsewhere, small birds are an important food item. Reptiles and
amphibians are typically eaten at the periphery of the Siberian weasel's range. Plant foods known to be eaten by Siberian weasels include
pine nuts and
Actinidia fruits. They typically eat about of food daily, and
cache excess food. In urban areas in China, Siberian weasels prey extensively on
rats. They are capable of killing and dragging the largest
fowls. Siberian weasels are active hunters and chase prey through snow, logs, water and people's houses.
Reproduction The
rutting period of the Siberian weasel varies depending on location. In western Siberia, it begins in early February to late March. In
Primorye, it begins in early March to late April. Six pairs of Siberian weasels in a fur
sovkhoz near
Moscow were in rut between 25 April and 15 May. They repeatedly mate during 35 minutes. The
gestation period lasts 38–41 days. There is one record of a female giving birth after only 28 days. Litters consist of 4–10 kits. They are born blind and are sparsely furred with white hair. They develop light yellow hair after a few days, and open their eyes after a month. They suckle for two months, and become independent by late August. By this time, the young have almost reached adult size, but still have their
deciduous teeth and lighter bones. Their fur is darker than that of adults. ==Subspecies==