Rodents and small mammals

Scotland is home to a multitude of small native mammals who play a key role in our ecosystem, including voles, mice, rats, shrews and moles. Not only do many small mammals help with seed dispersal, allowing native plants to thrive, but they have also been credited with controlling species of plants that could be damaging to crops

Incredibly, the burrowing activities of small mammals helps to mineralise soil. Furthermore, their toilet habits also add nutrients to the earth, making it more fertile! 

Whilst small mammals are key to controlling pest species of insects by eating them, they also play a pivotal role in supporting the survival of other important species in Scotland as they provide an essential food source for animals such as birds of prey and owls. 

 

Vole

Voles are characterised by their small eyes, short tail, little ears and rounded snout. Depending on the species, voles can have reddish chestnut, grey, dark brown or black fur.

On average, voles live between three and 12 months, however, larger species like the water vole can live for around 18 months. Voles are classed as rodents, which means an animal that has continuously growing incisors. 

 

Where do voles live?

Bank voles, field voles and water voles are widespread across mainland Scotland whilst Orkney voles can be found exclusively on five of the Orkney Isles. 

Bank voles make their homes in wooded areas, hedgerows, parks and gardens. They usually live in shallow burrows, however if the ground is unsuitable for digging, they may make grassy, round nests above ground. Field voles also burrow to make their homes but prefer to live in more open areas where there is long grass to shelter in. Water voles, as their name suggests, like to live around water so are most likely to be found near rivers, streams and ponds. Grassy banks along roadsides and ditches or grazed pastures make ideal homes for Orkney voles but they can also live on moorland and in bogs. 

 

What do voles eat?

A vole’s diet will vary depending on the species. Whilst bank voles enjoy foods like fruit, nuts and insects, the field vole prefers an herbivorous diet of leaves, grass and moss. Orkney voles like tucking into grass and herbs whereas a water vole will feast on foods from in and around the water, such as reeds, water plants, bulbs and even frogs and tadpoles. 

 

When are baby voles born?

The breeding habits of voles vary slightly from species to species, however, voles generally have multiple large litters per year in order to maintain stable population numbers. Many new born voles do not survive as they make easy prey for birds and larger mammals. 

 

Mouse

One of Scotland’s smallest mammals, mice are famed for their large rounded ears, pointy snouts and long tails. Most mice only live up to a year in the wild, mainly due to predation from larger mammals. Their incisors never stop growing, therefore they are scientifically classed as rodents. There are three species of wild mouse found in Scotland; the house mouse, field mouse and harvest mouse. The dormouse, although closely related, is actually a different species, despite having ‘mouse’ in the name! 

 

Where do mice live?

Although the house mouse is a wild animal, they have benefitted significantly from living around humans and are often found living in houses or outbuildings whereas other species will be more cautious of people. A field mouse’s natural habitat is woodland areas, rough grassland and gardens whereas a harvest mouse is more likely to live at the edge of the woods, in hedgerows or in longer grass.

 

What do mice eat?

Mice typically enjoy feasting on seeds, nuts, berries and insects but, depending on the species, will also nibble on fungi, vegetation and even snails. 

 

When are baby mice born?

Mice have several litters each year, usually between spring and autumn. Their litters can vary from as little as one pup to as many as nine, depending on the species. Their prolific breeding habits ensure that the species survives despite high mortality rates in the early stages of life.

 

Shrew

Shrews are very distinctive looking thanks to their long, pointed noses. They have small eyes and ears as well as short tails. 

Shrews need to eat 80 to 90% of their body weight each day and will not survive a few hours without food. 

Shrews have an average lifespan of one year and it is an offence to use prohibited means (including any trap) to kill or capture any species of shrew.

 

Where do shrews live?

Common shrews are widespread across mainland Scotland whilst pygmy shrews are also found in the Outer Hebrides. You are much less likely to see a water shrew as they are only found in certain parts of Scotland. 

 

 

Common and pygmy shrews can be found in any habitat where there is sufficient ground cover whereas water shrews make their homes near rivers, streams, ponds and lochs. Shrews take over burrows from other species and build cosy nests to sleep in. 

 

What do shrews eat?

Shrews are classified as insectivores, meaning they enjoy feasting on insects, worms, slugs and spiders. The water shrew is unusual amongst mammals because they have venomous saliva which is strong enough to paralyse frogs and small fish. They can tackle prey up to 60 times heavier than their body weight, including newts, frogs, crustaceans and snails.

 

When are baby shrews born?

Like other small mammals who don’t have a long life expectancy, shrews prolific breeding habits help to sustain a healthy population. Common shrews typically have litters of around six shrewlets, three to four times a year. Pygmy shrews have the same size of litter but females only tend to give birth once or twice each year. However, water shrews breed throughout the summer, giving birth to litters of three to fifteen young each time. 

 

Rat

Rats are incredibly adaptable and low maintenance mammals; as long as they have food and shelter they will be able to thrive in any habitat. 

The commonly spotted species of rat living in Scotland is the brown rat. They have grey-brown coloured fur, a pointed nose, large, bare ears and a long, hairless tail. 

Rats are classed as rodents, which means an animal that has continuously growing incisors. 

 

Where do rats live?

Rats have adapted to be able to live in any environment and can be found all over Scotland. They are particularly common around towns and cities where they have access to food waste left by humans. 

Brown rats live in loose colonies and dig underground burrows for resting and breeding. 

 

What do rats eat?

Brown rats are omnivores so will eat almost anything from fruit and seeds to human food waste, insects, birds' eggs or even small mammals. 

 

When are baby rats born?

Wild rats are famously good breeders. Female brown rats reach maturity at around three months old and have an average of five litters per year. Each litter contains up to 12 kits.

 

Mole

Often, the only evidence of a mole’s presence is a mole hill, a mound of earth that’s pushed up when they are digging underground tunnels. 

Despite rarely being seen above ground, moles are instantly recognisable. They have dark, velvety fur, broad, spade-like front paws for digging and a short tail.  Although they have no obvious ears and tiny eyes, they are neither deaf nor blind like many people believe. Their sensitive noses and whiskers help them navigate their burrows. 

Moles are active during the day and at night, taking short naps every three to four hours. Males may not return to their nest to rest for days at a time, instead sleeping in the tunnels. Mother moles will need to return to the nest four to six times a day to feed their young. 

 

Where do moles live?

Moles are found across most of mainland Scotland and on a few of the islands including Skye and Mull.

They live in underground burrows, rarely coming above ground. Well-constructed tunnel systems can be handed down from generation to generation. Moles prefer to live in woodland but can also adapt to agricultural land, coniferous forests, moorland, sand dunes and gardens so long as the soil is well-drained and deep enough for tunnelling.

 

What do moles eat?

Moles enjoy tucking into a selection of invertebrates such as earth worms, slugs and insect larvae, which they collect from their tunnels. They have a toxin in their saliva which can immobilise their prey. Moles must eat around half of their body weight a day to survive. 

 

When are baby moles born?

Female moles give birth to litters of three or four young in the spring. At birth, mole pups are naked and weigh as little as 3.5g but begin to grow fur at two weeks old. After around five to six weeks, the young are ready to leave their mothers to establish their own territories.

 

Common problems 

 

Pest control 

Sadly, small mammals are often seen as pests for a number of reasons; they can carry diseases and cause damage to food supplies, land and property. 

Generally, if there is no food left lying around for rodents and other small mammals, they will go elsewhere. It is an offence to use a prohibited means (including any trap) to kill or capture any species of shrew. Although the same protections do not apply to other small mammals, we would advise that non-lethal methods are exhausted before resorting to lethal measures. In any instance, we would expect lethal means of control to be carried out humanely. 

 

Disturbed nest 

If you have accidentally disturbed a nest with young in it, put it back to the way you found it. If it’s not possible to put the nest back where it was, carefully move it to safety, staying as close to the original location as you can so the mother can find them. Leave the nest alone and monitor for an hour. 

 

Orphaned young 

It is very unusual for any of these small mammals to be out in the open during the early stages of life. 

They are only likely to be out in the open if their burrow or nest has been disturbed or destroyed. Hand-rearing unfurred small mammals is rarely successful so if the animal is not injured or in immediate danger, keep your distance and monitor them. 

Their parents may return for them, however they will not be able to survive on their own and are at increased risk from predators. 

 

Predation 

Small mammals are under constant threat from predatory species like owls, pine martens and domestic cats. As part of the food chain, they support the survival of many other species whilst experiencing relatively low impact on their population sizes due to their fruitfulness when breeding. 

 

Sick or injured animals

If you come across a sick or injured animal, please put them in a plastic box, or place the box over them, and contact our helpline on 03000 999 999. 

Signs to be aware of include: 

• Signs to look out for include:
• Obvious injuries.
• Caught and injured by another animal.
• Lethargic or not moving.
• Tangled in litter.
• Surrounded by flies.
• Breathing problems.
• Twitching or falling over.
• Not reacting to noise.