European water vole

 - Neither a pig nor a rat, but a ”giant mouse”

Despite the Danish name of ’mosegrisen’ (literally bog pig), this animal is no pig, nor is it a water rat, like many people believe. The European water vole is related to the field mouse and is a ”giant mouse”, which can weigh 4-6 times as much as the field mouse. It often lives near wetlands where it can i.e. dig its den in the embankment along lakes, ponds, ditches and streams. It is a good swimmer and likes swimming around dense vegetation to find food. It eats grass, herbs, roots, seeds and fruits, and also small animals and snails.

Breeds like rabbits
You could say that European water voles ”breed like rabbits”. In the course of one year, it can have 5 litters with up to 5-8 offspring in each litter. The offspring only suckle for 3 weeks, and the offspring from the first brood have time to reach sexual maturity and breed the same year they are born. The European water vole does not live very long; most die or are eaten before they are two years old. The European water vole is prey to foxes, herons and birds of prey. Its worst enemy is the stoat, which can pursue the European water vole into its den. 

Every gardener’s worst fear
Like a mole, European water voles can damage the garden. It digs long tunnels just below the soil surface, and can also make molehills. European water voles molehills can be recognized from the moles’ in that they are surrounded by 6-8 cm large holes. European water voles can damage trees, shrubs and perennials in the garden. It particularly likes to eat the roots of fruit trees, which cannot survive an attack from a European water vole. European water voles can become serious pests particularly in orchards.

Track: European water voles’ footprints look like big mouse tracks. The European water voles are mostly discovered when you see their tunnels and molehills. If you walk along a stream, you can sometimes hear a plop sound when the vole jumps into the water.

Facts: A European water vole weighs 200-300 grams, and the body is about 12-20 cm, while the tail is about 10-15 cm long. The head has a round shape and the ears are small. Like other rodents, it has large incisors that continue growing throughout its life. The thick fur is dark brown on top, while the underside is grey-white or light brown. The European water vole is widespread throughout Denmark and can live in both wet and dry areas. It is considered a pest in private gardens.