Water voles (Arvicola terrestris) typically live along the banks of water bodies such as rivers, streams, ponds, lakes and marshes and are the UK’s fastest declining mammal. Signs that water voles may be populating an area include burrows in the riverbanks or piles of nibbled grass and stems, as water voles like to sit and eat in a stationary position. Their droppings are fairly large and cigar-shaped. Water voles are much larger than other voles and are often confused with brown rats when, in fact, water voles have more rounded noses and smaller ears that do not protrude from the head.


  • According to the International Union for Conservation of Nature (IUCN), the water vole is a species of ‘least concern’ worldwide and it is fairly common in some European countries. However, it is thought that in the UK the water vole population may have dropped by as much as 90 per cent. The People’s Trust for Endangered Species (PTES) estimates a UK population of around 875,000 individuals.
  • Water voles are mainly threatened by habitat loss through urbanisation and development beside waterways. Their habitat is also being destroyed by livestock trampling and overgrazing, which strips the grasses and plants from river banks.
  • Water vole decline can also be attributed to the introduction of the American mink. In 1920, American mink were brought to the UK for the fur industry. The captive mink escaped from the fur farms, or were released, and since then the opportunistic predators have decimated water vole populations.
  • Despite what you might think, water voles are active during the day and don’t hibernate in winter — although they may spend more time in their burrows.
  • There is a population of water voles in Glasgow which don’t actually live alongside a waterway at all and have adapted by creating their borrows in fields. Research by the University of Glasgow found that this population of terrestrial water voles is the biggest population of water voles in lowland Scotland.
  • Ratty, from The Wind in the Willows, was not a rat at all, but a water vole.
  • Water voles are mainly herbivores and like to eat grasses, reeds, sedges, roots and fruits. A recent study reported that water voles can eat an enormous variety of plants with over 220 different plants recorded in their diets. Occasionally they will eat insects and invertebrates to supplement their diet if needed.
  • Water voles spend a long time eating. They need to eat 80 per cent of their body weight every day.
  • Water vole reproduction begins in March and is followed by a gestation period of just 20-30 days. Females can produce two to five litters annually. When pups are born, they are blind and hairless and stay with the female for around 28 days before leaving their burrow. Families of water voles tend to stay in close proximity with colonies of up to 10 individuals.
  • Females have territories of 20-150m when breeding and fiercely defend them whereas males have much larger ranges of 60-300m that may overlap several females.
  • Water voles demark their boundaries with their droppings which they flatten into the ground. Their droppings are not scented so they rub their hind feet on their scent glands on their chests which they stamp on their droppings to scent them.


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