The common shrew, 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 long and weighs 5 to 12 grams, 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.

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 square meter. While this sounds reasonably big, it is a square 20-25m square – really rather small (between 16 and 25 of these territories will fit in 1 hectare (2.5 acres)). 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.

The common shrew’s carnivorous and insectivorous diet consists of insects, slugs, spiders, worms, amphibians and small rodents. However, given shrews need to consume 200 to 300% of their body weight in food each day in order to survive, a shrew must eat every 2 to 3 hours to achieve this goal. A shrew will starve if it goes without food for more than a few hours. They do not hibernate in the winter because their bodies are too small to store sufficient fat reserves.

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%, and 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 dropping temperatures trigger their bodies to breakdown bones and tissues and absorb them. As temperatures start to rise with the onset of spring, their bodies start to rebuild the lost bones and tissues. 

This significantly reduces their food requirements and increases their chances of survival in the winter. Additionally, common shrews exhibit three distinct seasonal phenotypes; however, these phenotypes have the same relative oxygen consumption despite varying temperatures. The ability for the body to shrink and reabsorb nutrients from those parts of the body that might disappear, is quite impressive, as a reduction of 20% of body weight, is quite a significant quantity of energy. Yet, a 20% loss of size, would still be more than large enough to take its prey.

Shrews have poor eyesight and instead use their excellent senses of smell and hearing to find food.

The common shrew breeding season lasts from April to September, but peaks during the summer months. After a gestation period of 24 to 25 days, a female gives birth to a litter of five to seven babies. A female rears two to four litters each year (this means a pair of shrews can have almost 30 offspring in one year. The young are weaned and independent within 22 to 25 days.

Young shrews often form a caravan behind their mother, each carrying the tail of its sibling in front with its mouth.

A study in 2019, showed that shrews can use echolocation, though how much they use this is not immediately clear.

The common shrew is not an endangered species, but in Great Britain it, like other shrews, is protected from certain methods of killing by the Wildlife and Countryside Act of 1981. In Britain, shrews can be found at densities of up to one per 200 square meters(240 yd²) in woodlands. The main predators of shrews are owls, cats, weasels, snakes, stoats, and red foxes. They are not generally a species that people regularly encounter, but should you be out at the right time of day, in the right place, it is likely to be easier to see than many other species. It is the kind of species, which if you encounter regularly, offering to show people is likely to be worth something. We hope to list these. Do get in touch if you are interested.