The Siberian Mouse, or Korean field mouse (Apodemus peninsulae), is a widespread and ecologically significant rodent species across Northeast Asia. This small mammal plays a considerable role in forest ecosystems, acting as both a primary consumer and a seed disperser. Understanding this species requires examining its defining physical attributes, its expansive natural range, the specific food sources that sustain it, and the details of its life cycle.
Physical Characteristics and Identification
The Siberian Mouse is a medium-sized member of the Apodemus genus. An adult typically measures between 76 and 125 millimeters in head-and-body length. The tail is notably long, often reaching a length nearly equal to the body, ranging from 75 to 112 millimeters.
The coat displays a muted, grayish-brown or sometimes rusty tint dorsally. This upper coloration contrasts sharply with the paler, grayish-white fur covering the belly and underparts. Its features include relatively large eyes and ears, which are adaptations for navigating dense undergrowth and low light. Identification relies on this combination of size, the bi-colored coat, and the proportional length of the tail.
Geographic Range and Preferred Environment
This species is widely distributed across Northeast Asia, with its range extending from the Russian Far East and Southern Siberia eastward across Mongolia and Northern China. Populations are also well-established on the Korean Peninsula and the Japanese island of Hokkaido. This extensive distribution demonstrates adaptability to varied temperate climates.
The preferred environment ranges from dense temperate forests and mixed woodlands to shrublands and open glades. It often thrives in ecotones, transition areas between forest edges and agricultural fields, demonstrating tolerance for human-altered landscapes. For shelter, the mouse constructs simple burrow systems, typically excavated at shallow depths beneath the soil surface. These burrows usually contain a central nesting chamber lined with dry vegetation, providing insulation and protection from predators and harsh weather conditions.
Dietary Habits and Nutritional Needs
The Siberian Mouse maintains an omnivorous diet, though it is primarily granivorous, exhibiting a strong preference for plant-based materials. Seeds and fruits form the bulk of its nutritional intake, especially those from forest trees like acorns (Quercus species), pine nuts (Pinus koraiensis), and hazel nuts (Corylus shrubs).
Foraging behavior is intensely focused on collecting and transporting these nutrient-dense items, a process that becomes more frequent in the late summer and autumn. This activity is directly linked to food caching, an adaptation crucial for survival during the colder, less productive winter months. The mouse stores large quantities of seeds in its burrow systems, ensuring a sustained food supply. While seeds are dominant, the diet also includes insects, fungi, and green vegetative matter, especially during the warmer seasons.
Social Structure and Reproduction
The Siberian Mouse is primarily a nocturnal and crepuscular species, with peak activity occurring after sunset and before sunrise. While generally considered a solitary forager, its social structure adapts seasonally, notably forming winter aggregations. These small groups often share a single burrow system, a behavior that conserves energy and helps maintain body temperature in cold environments.
Reproduction typically begins in the spring and continues through the autumn, though the exact duration is influenced by local climate and food availability. The gestation period is short, lasting around 19 to 21 days. Females are prolific, capable of producing multiple litters per breeding season, allowing populations to rebound rapidly. Litter sizes generally range from three to six pups, which are born altricial (blind, hairless, and completely dependent on the mother). Sexual maturity is reached within a few months, contributing to a quick turnover of generations. In the wild, the lifespan is short, often less than a year, but captive individuals may survive for up to two years.