12 fascinating facts you might not know about water voles

The European water vole is a large species of rodent found throughout much of Britain, but has undergone a serious decline in numbers. 

Water vole, Arvicola terrestris, Kent, August 2009

Water voles are active during the day © Mike Lane / Getty


1. Water voles disappear over winter but don’t hibernate

Overwinter, water voles go under ground and maintain energy levels by sleeping more, and by laying down stores of tubers, bulbs and rhizomes.

One farmer uncovered a hundredweight of potatoes cached in a ditch, presumed by water voles.

2. Highly territorial

Although water voles hunker down together throughout winter to keep warm, aggression is triggered again in February and they become highly territorial throughout the breeding summer months.

3. Unwanted aliens

Before 2000, mink regularly escaped or were released from Britain’s fur farms. These alien invaders pose one of the biggest threats to water vole survival as they predate on the native rodent.

Discover 9 more invasive species causing problems in the UK

4. Water dog?

The water vole is sometimes known as the water dog, or even water rat in some areas around the country.


Water voles are excellent swimmers. If disturbed, they dive into the water with a ‘plop’ © Mike Lane / Getty

Find out how to tell the difference between a water vole and a brown rat

How to identify water vole (and other mammal) droppings

5. A winter siege

These rodents plug some of their burrow entrances with a mixture of mud and vegetation to help maintain heat in their burrows through winter

6. A squeaky escape

Although water voles are on the up at the moment, at one point they were the fastest declining species in Britain.

Between 1989 and 1998, the population fell by almost 90 per cent. Hopefully with continued conservation efforts they have escaped extinction.

Where to see water voles in the UK

View this gallery from wildlife photographer Nick Upton on water vole reintroduction

7. Compost radiators

Voles have galleries that they excavate for storing compacted waste. These chambers are full of food scraps and excrement that will decompose and help to generate heat throughout the cold winter months

8. Separation from the Scots

Scottish water voles have a completely different ancestry to their southern cousins across the border. Voles to the south of Scotland migrated over from south east Europe, recolonizing after the Ice Age. Scottish voles came from the Iberian Peninsula.

9. Hungry rodents

Water voles eat 80 per cent of their own body weight every day.


Water voles often sit and eat in the same place, creating a pile of nibbled grass stems © Mike Lane / Getty

Find out more about water vole behaviour

10. Not all water voles like water

Water voles in mainland Europe don’t actually live near water at all, but borrowed in underground systems more like that of a mole.

11. Scent marking

Water voles don’t use faeces or urine to scent mark. Instead, they actively scratch flank glands with hind-feet at latrines and during agonistic and sexual encounters.

12. Short lived

Water voles usually live a maximum of two winters. However, they can raise two litters each year with up to five offspring in each brood.

Water vole emerging from a drainage pipe

Water voles are much bigger than other vole species, and can sometimes be confused with brown rats © Jamie Hall / Getty


Read more wildlife facts in BBC Wildlife Magazine