Water vole

Scientific name: Arvicola terrestris

Country: Albania, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, China, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Georgia, Germany, Greece, Hungary, Iran, Iraq, Israel, Italy, Kazakhstan Latvia, Lithuania, Luxembourg, Macedonia, Moldova, Mongolia, Netherlands, Norway, Poland, Portugal, Romania, Russia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Syria, Turkey, Ukraine, United Kingdom, Yugoslavia

Continent: Europe, Asia

Diet: Grass - gramnivore, herbs - forbivore, fruits - frugivore.

Food & feeding: Herbivore

Habitats: Freshwater, temperate forest and woodland

Conservation status: Not Threatened

Relatives: Rat, Capybara

Description: They are of similar size to the brown rat, with head and body length of 120 to 220 mm, and a tail that is 65 to 125 mm. In fact sometimes they are referred to as 'water rats' although they are not true rats at all. They weigh between 70 and 250 grams. Their coat, like many aquatic mammals has two layers. Long dark guard hairs on the outside and soft woolly underhair closest to the skin. This combination traps air and helps keep these tiny creatures warm when they dive into the cold water. Flaps of skin inside their ears also keep the water out. Like all rodents, they have well-developed front incisor teeth that grow continuously, ideal for gnawing away at plant stems, their favourite food.

Lifestyle: In Britain water voles live in the banks of rivers, canals, lakes and ditches. They live in burrows with multiple entrances, just above the waterline. They enter the water to dive for tasty waterweeds or to escape from predators. They can even create a smokescreen to confuse predators, by stirring up the mud in the water. On land they nibble grasses, herbs and fruits. They are particularly fond of apple a good way to attract them into the open where you can watch them more easily. Strangely, Water Voles elsewhere in Europe often live far away from streams and rivers, in extensive burrow systems in grassy areas.

Family & friends: European Water Voles seem to share their burrows with a mate and perhaps two generations of young. British Water Voles seem to be less social. Chance meetings outside of the breeding season with strangers often end in a conflict.

Keeping in touch: Males scent-mark their burrow systems by raking their hind feet over scent glands along the sides of their bodies. When males meet, they will often fight, making high pitched squeaks that can be heard several metres away.

Growing Up: Water voles can breed very rapidly, up to five litters of 5-6 pups per year. When born they are pink, hairless, and weigh only 5 grams. By 5 days they are covered in fur and by 7 days their eyes are open. Only a third of these youngsters will survive to adulthood, and even then they are unlikely to survive more than two winters. They are eaten by many predators: pike, herons, stoats and the introduced American mink. The average lifespan is a little over 5 months.

Conservation news: While not threatened on a global level, Water Voles are one of the most threatened mammals in Britain. A survey conducted in 1990 revealed that Water Voles had disappeared from 68% of the sites that they had been found in a few decades earlier. The main causes for their decline include destruction of bankside vegetation, pollution, and the introduction of the American Mink, an aggressive predator. It is now a legal offence to disturb Water Vole burrows.

Did you know?

The character Ratty in Kenneth Grahame's popular children's book Wind in the Willows is based on a Water Vole. In Russia on the other hand, they have a different view of these small cute rodents: Water Voles are hunted for their fur, it takes an awful lot of voles to make a coat.