Common shrew

Common shrews have to eat every 2-3 hours to survive their short lives, which usually only last one year.  Though small in size, common shrews are very territorial and aggressive and can be heard fighting on occasion, emitting high-pitched squeaks during summer. 

Taxonomy chart

Animalia - Chordata - Mammalia - Eulipotyphla - Soricidae - Sorex - Sorex araneus

Conservation status: UK Red List

GB: Least Concern

England: Least Concern

Scotland: Least Concern

Wales: Least Concern

Global: Least Concern

Summary

Diet: Mainly insects but also earthworms, spiders, small slugs and snails. 

Habitat: Urban and gardens, deciduous woodland, grassland, mixed woodland, arable land. 

Size: Weight: 5-14g. Length: 5-8cm, tail: 2-4cm. 

Lifecycle: Average lifespan: 1-2 years, although it is rare for them to live longer than 1 year. 

Conservation concerns: Protected in the UK under the Wildlife and Countryside Act, 1981. 

Terminology

Caravan: A link of common shrews following their mother, usually because the nest has been disturbed or to encourage exploration of their environment. They hold each other at the base of the tail.  

Vibrissae: Stiff hair such as whiskers which can act as tactile organs. 

Echolocation: A method of determining the location of objects using projected sound waves, which reflect back to the emitter. 

Ultrasound: Sound waves above the frequency of human hearing. 

Geography

The common shrew can be found throughout mainland Britain and has been introduced to many islands - though not Ireland, the Outer Hebrides, or Shetland. Their habitat includes hedgerows, scrubland, gardens, deciduous woodland, grassland, mixed woodland, and arable land. 

Since common shrews need to feed regularly (see biology section) they spend most of their time on the surface in search of food. However, they live in burrows made and abandoned by other animals. Common shrews do not hibernate, but they become less active during winter. During winter, their size shrinks to require less effort to move, which some scientists suggest could result in a lower need for food. Their liver, brain, and even skull shrinks during this time! 

Biology

Common shrews have a length of 5-8cm, a tail measuring 2-4cm, which is only half the length of its body, and weigh 5-14g. These tiny creatures have an average lifespan of 1-2 years, although one year is more common. The appearance of the common shrew is a small creature with tiny eyes, small ears and a long nose, giving its face a pointy shape. Its fur is dense and velvety, the colouring is dark brown on its back, grey or silver underneath, and pale brown on the sides.   

Common shrews are very territorial animals who only meet each other voluntarily during mating season which happens from April to August. Between May and September, female common shrews can have three or four litters of 5 to 7 young. Each litter can have a different father. Young shrews occasionally will follow their mother in a ‘caravan’ where each link of this caravan grasps the base of the tail of the preceding link. This is often associated with disturbance of the nest and to encourage the young to explore their environment. Once the young are 25 days old, they are weaned.  

These tiny creatures have excellent hearing, sent, and feeling thanks to a long nose and sensitive whiskers. These whiskers are known as vibrissae. Their sense of smell is necessary for exploring territory, and their whiskers are used to identify potential prey. Common shrews are also able to produce ultrasound to help them navigate their environment, though this usage is limited in comparison to other mammals such as bats. They emit ultrasonic sounds while fighting, afraid, courting, and possibly even when hunting. 

Common shrews have a heart rate which can reach 500-1000 beats per minute. Due to the ratio of their surface area to volume, they cannot retain heat for long. This means that to stay warm, they have a high metabolic rate and a short lifespan. Their metabolism means they need to be constantly on the move, day and night, taking only short naps before finding something to eat. They need to eat every two to three hours to survive.  

Ecology

Common shrews are active both day and night and mainly feed on insects but also consume earthworms, small slugs and snails. Some of the earthworms they eat are 10cm, meaning they can hunt prey larger than themselves. They can locate prey up to 12cm beneath the soil’s surface. To survive, common shrews have to eat 80-90% of their body weight every day!  

Natural predators of common shrews include tawny owls and barn owls. Occasionally weasels, foxes, stoats, and kestrels will also prey upon them. Thanks to a liquid produced from the common shrew’s gland, their skin tastes foul, meaning they often are abandoned by the predator.  

Common shrews are known to carry a large number of parasites, which are transmitted to them by their prey.  

Conservation

Common shrews are classified as ‘least concern’ on the UK Red List across Great Britain overall. They are protected under Schedule 6 of the Wildlife and Countryside Act (1981) in the United Kingdom. Common shrews are one of the most numerous mammals in the British Isles.  

Despite being quite common, common shrews still face some threats, including potentially from the non-native greater white-toothed shrew, as well as from habitat loss due to changing farming practices, growing urbanisation, agricultural pesticides, and pollution.  

History

Common shrews have been present in the British Isles since the end of the last ice age. 

The connotation of shrews with something negative sees its first mention with the ancient Romans. Most shrews were considered dangerous as they were thought to have venomous bites (now we know that only water shrews of the British shrews are venomous), and the ancient Romans thought contact with a shrew would cause lameness in animals.  

The Bodleian Bestiary (mid-13th century) sees the mentioning of a human shrew, which refers to ‘greedy men who seek earthly goods and make the good of others their prey’. During this time, shrew also became a nickname for the Devil, and ‘I beshrew thee’ was used as a saying to invoke harm during the Medieval Age. It is Chaucer who continues equating shrews with greed for men, but also makes the first written references to women as shrews. Examples where this can be read are ‘The Pardoner’s Tale’ and ‘The Wife of Bath’s Tale’. By the time Shakespeare wrote ‘The Taming of the Shrew’, the reputation of shrews and their meaning was already well established. 

In Edward Topsell’s ‘Historie of Foure-Footed Beasts and Serpents’ (1658), the shrew does not get a good entry. The creature is considered a ravening beast, and upon touching it, the shrew would bite and poison you. Its character is deemed cruel, and the creature is unloved because everybody fears it. The ancient Roman superstition that shrews cause lameness in farm animals confirmed their dangerous nature. These instances could be counteracted by making a stick from the ‘shrew ash’ and applying it to the farm animal. This stick was a twig from an ash tree into which a shrew had been placed into a hole in the trunk and sealed up. 

How to identify

Identifying characteristics: Tri-coloured coat, 2-4cm tail. 

Footprints: Same as all shrews, these will be very faint, with five toes on the front feet. 

Nests: Small loose nests of grass and other vegetation in tussocks and undercover. Occasionally found in local dormouse nest boxes.  

Surveying period: Year-round. 

Recommended reading

Searching for Shrews — Mammal Society

Frequently asked questions