Habitat: In the British Isles water voles live in burrows that they dig in the banks of slow flowing lowland rivers or in ponds and streams – wherever the water level remains fairly constant. They are also occasionally found further upland. Within their burrows they build ball shaped nests of grass and other plant material. They may also build these nests under driftwood or on the water bank, if there is thick vegetation.

In central Europe, the Soviet Union, and parts of Asia, water voles are more similar to moles in their lifestyle. In these regions they may be found far from water, burrowing close to the surface in woodlands, meadows, and even gardens. North American water voles are semi-aquatic. In the summer they often build tunnels that link their burrows to nearby waterways. In winter they move away from the water and build their nests under the snow.

Breeding: Breeding generally begins in March and may continue until late fall. Females usually have three or four litters a year. The young of the first litter may produce litters of two by the end of summer. The water vole’s gestation is 20 to 22 days, and up to eight young may be born. By 5 days the young have their furry coats, and 3 days later they open their eyes. They are weaned at 14 days, by which time they are about half the adult size. Babies are born blind and naked, weighing less than two-tenths of an ounce.

Behavior: The male water vole has a range of over 425 feet of water bank; the female somewhat less. To mark its territory, the male rakes its hind feet over its flank gland and pushes out a secretion that it then stamps into the ground with its hind feet. Water voles generally do not form large colonies. Those that live on dry land may form groups consisting of the adult pair and two generations of young. Water voles will fight if they are overcrowded, uttering high, shrill squeaks. Water voles swim and dive with great skill.

Food and Feeding: Active by day and night, the water vole eats mainly grasses and waterside plants. It tears at the plant stems and pushes them into its mouth with its front paws. It will also eat twigs, buds, bulbs, roots, and fallen fruit. In Europe, when seasonal conditions provide plenty of food for several years, “plagues” of water voles may occur. They eat greedily, leaving green pastures looking almost like deserts, undermined with burrows. The population then drops dramatically, probably because of a lack of food. Water voles gnaw the roots of young trees.

Naturewatch: it is easy to confuse a water vole with a water rat, but in fact its muzzle is blunter, its tail is shorter, and its back is not quite as arched. Also, its fur is soft and shaggy, while the rat’s is stiff and sleek. Like the rat, the water vole is usually brown, but it can also be black. A water vole’s presence can often be detected by its greenish, cylindrical droppings. These tend to be deposited around the edges of its range.

Key Facts:
Sizes:
Length: 6-9 in. Tail, to 6 in.
Weight: 5-11 oz.

Breeding:
Sexual maturity: 5 weeks in females in some locations
Breeding season: March to October
Gestation: 20-22 days
No. of young: Usually 4-6

Lifestyle:
Habit: Lives in small family groups
Diet: Mainly grasses and waterside plants
Call: Rasping squeak when frightened; high, shrill squeak when fighting
Lifespan: About 5 months in the wild; up to 5 years in captivity

Related Species: There are 3 species of water vole worldwide.
Distribution: Found in most of Great Britain, Europe (except Scandinavia and southern areas), and part of the Soviet Union. Also in southwestern Canada and northwestern United States.
Conservation: Water voles are hunted for their fur in the Soviet Union but are considered pests in Europe. In Britain their numbers have declined in the last decade.

The Water Vole’s Aquatic Life:
Smoke screen: When chased underwater by an enemy such as an otter, the vole raises a cloud of mud that acts as a smoke screen.
Burrow: There are several underwater entrances to the burrow, providing easy access – and a good escape route if chased by a predator.

Did You Know:
During its first week the water vole gains more than a quarter-ounce.
A female water vole can give birth 22 days after its previous litter.
More than 40 water voles may live on one acre.
In Holland, water voles can threaten the tulip harvest because they eat the tulip bulbs in winter.

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