The common shrew (Sorex araneus), also known as the Eurasian shrew, is the most common shrew, and one of the most common mammals, throughout Northern Europe, including Great Britain, but excluding Ireland. It is 55 to 82 millimetres (2.2 to 3.2 in) long and weighs 5 to 12 grams (0.2 to 0.4 oz), and has velvety dark brown fur with a pale underside. It is one of the rare venomous mammals. Juvenile shrews have lighter fur until their first moult. The common shrew has small eyes, a pointed, mobile snout and red-tipped teeth. It has a life span of approximately 14 months.
Shrews are active day and night, taking short periods of rest between relatively long bursts of activity.
Territory
Common shrews are found throughout the woodlands, grasslands, and hedgelands of Britain, Scandinavia, and Eastern Europe. Each shrew establishes a home range of 370 to 630 m (440 to 750 yd²). Males often extend the boundaries during the breeding season to find females. Shrews are extremely territorial and will aggressively defend their home ranges from other shrews. They make their nests underground or under dense vegetation.
Diet
Common shrew foraging (UK)
The common shrew's carnivorous and insectivorous diet consists of insects, slugs, spiders, worms, amphibians and small rodents. Shrews need to consume 200% to 300% of their body weight in food each day in order to survive; to achieve this they must eat every 2 to 3 hours, and they will starve if they go without food much longer than that. They do not hibernate because their bodies are too small to store sufficient fat reserves and they have a short fasting duration.
Common shrews have evolved adaptations to survive through the winter. Their skulls shrink by nearly 20% and their brains get smaller by as much as 30%. Their other organs also lose mass and their spines get shorter. As a result, total body mass drops by about 18%. When spring returns, they grow until they reach roughly their original size. Scientists believe that low...
