This is the largest order of mammals with the majority of the 1700+ species worldwide being mouse or rat sized. They occupy all terrestrial and aquatic habitats often living at very high densities. Fifteen species live in Britain, seven of which were introduced by humans. In Devon we have some knowledge on the presence or absence of some of the species of conservation concern, but few systematically collected records exist for the others. Records for the smaller species may often come from owl pellets. Devon is known to support high quality habitat for species such as dormice, is thought to have no more watervoles, but has an abundance of habitats that will support the range of mice and voles described below.

Rodent Family Groups
Rats and mice – Family: Muridae
Voles – Sub-family: Arvicolinae
Dormice – Family: Gliridae
Squirrels - Family:Sciuridae

Know your nibbled nuts
Only 5 species generally eat hazel nuts – grey squirrel, wood mouse, yellow-necked mouse, bank vole and dormouse.

Grey squirrel:
Using its powerful teeth like a crowbar the grey squirrel prizes the nut open from the top causing the nut to crack open with clean edges.

Wood mouse/yellow-necked mouse:
Gnawing as the side of the hole furthest away from its body it creates a round hole with a ring of tooth marks surrounding it and vertical tooth marks on the cut edge. Wood mice also eat the pips of fruits such as cherries and sloes in a similar way.

Bank vole:
The bank vole inserts its nose into the hole and gnaws at the nearest edge leaving a clean-edged hole with no tooth marks around the outside and the cut edge rough with vertical tooth marks. Bank voles tend to eat the flesh of fruits and leave the stones uneaten.

Dormouse:
The hole is definitely smooth and round inside with oblique tooth marks around the cut edge. It also leaves other tooth marks around the outside like wood mice and yellow-necked mice as it gnaws the hole furthest from its body. The hole usually encompasses the softer base of the nut.

(Clethrionomys glareolus)

Found in banks, hedges, rough grassland, scrub and deciduous woods; they like plenty of cover. Sometimes found in buildings (greenhouses, sheds etc.). Probably common and widespread across Devon but extremely under-recorded.

Weight: 15 – 25g (juv. less than 14g)

Head-body length: 90 – 100mm

Tail length: 40 – 50mm

Colour: Chestnut head and back, pale grayish-brown under parts.

Food: Seeds, fruit, roots, grass, insects and earthworms

Habitat: Areas of good ground cover including hedgerows, scrubland, deciduous woodland and
Sometimes in gardens.

They are active both during the daytime, and at night and their territory and feeding grounds can be up to 50 meters and within that area they will often climb bushes to feed on the fruit.

(Microtus agrestis)

Rough grassland, open woodland, sometimes in buildings. Probably common and widespread across Devon but seriously under-recorded.

Weight: 20 – 40g (juv. less than 15g)

Head-body length: 90 – 120mm

Tail length: 31 – 46mm

Colour: Dark brown with shaggy coat

Food: Herbaceous plants and grasses, occasionally fly larvae and in the winter they will gnaw bark.

Habitat: Grassy fields, young plantations, open woodland, mountain heath and dunes. There must be enough ground cover for them to hide from predators.

They are a very important food source for many predators and the scent that they use to mark their runways gives off ultraviolet radiation which, unfortunately for the vole, is easily picked up on by predators such as barn owls and kestrels hunting overhead

Closely associated with freshwater, preferring steep banks with plentiful and varied vegetation. Once widespread and common in Devon, it has suffered a dramatic decline in the last 20-30 years and may now be extinct in the county. Concerted survey effort over the last 2 years has failed to locate any water voles in Devon.

(Muscardinus avellanarius)

Found in broadleaved woodland, dense scrub, coppice woodland, hedgerows (very occasionally comes into buildings and will use nest boxes). It is only found in the southern parts of England and Wales - Devon is a stronghold for this protected species. The dormouse has been the subject of a number of special surveys and is more widely recorded than other rodents in Devon.


Weight: 15 – 30g

Body length: 60 – 90mm

Tail length: 55 – 80mm

Colour: Yellow-brown coat with entirely furry tail.

Food: In spring they will eat flowers, pollen and honeysuckle. If these are not available they will eat hazelnuts, fruits, sweet chestnuts, beech mast and aphids and other small insects in autumn.

Habitat: Overgrown hedgerows and deciduous woodlands.

Dormice spend most of their time, when awake, high up in trees, climbing from branch to branch to find food and escape predators at ground level. They will usually only come down to hibernate just beneath the leaf litter on forest floors. When they come out of hibernation they build nests in the undergrowth where they will stay to get out of harsh weather. They can also go into torpor, curling up into a ball, to save energy during times when food is scarce. Dormice spend a very large proportion of their lives asleep!

(Apodemus sylvaticus)

Woodland, arable land, gardens, scrub, quite often in houses and other buildings. Probably widespread and common throughout Devon, it is seriously under-recorded though often seen - particularly by cat owners! Often confused with the house mouse when seen indoors.

Weight: 15 – 25g (juv. less than 14g)

Head-body length: 80 – 100mm

Tail length: 80 – 90mm

Colour: Yellowish-brown head and back and grey under parts.

Food: Mostly seeds but also fruit, snails, insects, fungi, nuts, buds, moss and tree bark.

Habitat: Fields, grassland and hedgerows, but mainly in woodlands. They are quite common garden species, especially in winter.

They breed between March and October and become sexually mature at just 2 months old. One female can have up to 5 litters of 4-8 young a year meaning one pair could produce up to 40 young in one breeding season!

(Mus musculus)

Commonly associated with human habitation in urban and rural settings but may live in hedgerow and more open habitat. Its worldwide distribution is greater than any other mammal excepting humans - so undoubtedly widespread and common in Devon. Hardly any records in the Devon database!

Weight: 17 – 20g

Head-body length: 70 – 90mm

Tail length: 77mm

Colour: Grey-brown fur, pink feet and ears and a long dark tail.

Food: Fruit and grain, insect larvae, worms and insects.

Habitat: Woods, hedgerows and open fields, close to human houses, rubbish tips and farms where it is easy to escape competition for food and shelter.

Their feeding grounds can be as small as 4 meters and as big as 2 kilometers, depending on the availability of food and shelter.

(Apodemus flavicollis)

Mainly woodland, hedgerows, field margins, orchards and wooded gardens. Only in the southern half of Britain and much less common than the wood mouse. Probably uncommon or rare in Devon - it is easily confused with the wood mouse so possibly under-recorded in Devon - though a survey 3-4 years ago yielded only one confirmed record.

Weight: 20 – 40g (juv. less than 20g)

Head-body length: 90 – 120mm

Tail length: 90 – 130mm

Colour: Similar colourings to Wood mice, but with a more orange tint to the fur, also they have a band of yellow fur running between their two front legs, giving them the name “yellow-necked”.

Food: Fruit, buds, seedlings, insects and grubs.

Habitat: Mostly found in woodlands, but also inhabiting hedgerows and orchards.

They often jump around and bite when they are caught, they can jump up to 90cm to try and avoid capture by a predator!

(Micromys minutus)

Found in long grass (hay meadow, field margins), reed beds, cereal fields, woodland edge. Probably found throughout Devon where the habitat is suitable though there is some evidence of local decline. Extremely under-recorded though nests are easily found.

Weight: 5 – 9g (juv. less than 5g)

Head-body length: 50 – 70mm

Tail length: 50 – 55mm

Colour: Reddish-yellow fur with white under parts, furry ears and a blunter nose than other mice.

Food: Grass seeds, grain, berries, fruit and insects in winter.

Habitat: Hedgerows, reed-beds, cornfields, brambles, long grass and open fields.

Harvest mice are Europe’s smallest rodent and weigh about the same as a 2 pence piece! They are also the only British mammal with a prehensile tail which allows them to hold onto blades of grass making them very skilful at moving through the tops of long grass.

Generally associated with people though some populations may be found in field margins and crop fields. The brown rat is an introduced species, first recorded in England in 1728 and now widespread in urban areas throughout Devon and the UK. It is another common species which is under-recorded in Devon.

Occurs in woodland, hedgerow, trees, parks and gardens. Introduced from the USA to about 30 sites in England and Wales between 1876 and 1929 - now common south of Cumbria, including Devon. It is well recorded in some parts of Devon and under-recorded elsewhere.