As December draws to a close, let's talk about one of the smallest predator species in Latvia – the stoat (Mustela erminea).

Currently, the stoat's fur is white, but in summer, it changes to brown with a whitish throat and belly. The tail is three times shorter than the body and has two colors – brown during summer and white in winter. The tail tip is always black. The easiest way to distinguish a stoat from a weasel is by its tail: the stoat's is longer, slender, and bi-colored, while the weasel’s tail is noticeably shorter, stubbier, and single-colored.

The stoat is a predator with a slender, flexible body. It measures 20–27 cm in length and weighs up to 200 g. Stoats are crepuscular and nocturnal but can be active at any time of day. They remain active year-round.

Habitat and Behavior

The stoat lives in forest edges, shrublands, and, most commonly, along water bodies and small low-lying marshes. In winter, it may settle near human habitation, including rural homes. It hides in piles of stones, branches, or logs, fallen tree hollows, and burrows. Females create a permanent den only during the breeding season (March–May).

Their primary prey consists of vole-like rodents, which they primarily hunt in burrows. They also eat shrews, frogs, lizards, insects, birds and their eggs, and wild berries. Stoats are efficient hunters and, if food is abundant, will kill more prey than they can eat, storing the excess as reserves.

Reproduction

Stoats are polygamous and reproduce once a year. Litters can range from 3 to 18 kits, averaging 4–9. The female alone cares for the young.

The kits grow rapidly and can hunt with their mother by the eighth week. While females reach adult size at least six weeks after birth, they can mate as early as 60–70 days old, often before they are weaned. Males, however, do not reproduce or reach full size until their second summer.

Females in the wild typically survive at least two breeding seasons, while males often do not live as long. Reproductive success largely depends on food availability.

Den and Threats

Stoats rest and den among tree roots, hollow logs, or abandoned burrows taken over from rodents (stoats do not dig their own burrows). An individual’s territory includes multiple dens lined with dry vegetation or fur and feathers from prey. In times of plenty, stoats store food in side chambers of burrows.

In Latvia, the threats to stoats have not been well studied. However, similar to other regions, stoats may be affected by agricultural and forestry intensification, leading to habitat loss and reduced prey availability. Populations are also limited by the invasive American mink, which preys on stoats and competes for food.

The stoat is classified in Latvia as a species with insufficient data (DD, Data Deficient) to fully assess its conservation status.