How to tell the difference between a brown rat and a water vole
When all you've seen is a flash of brown fur, it can be hard to know whether it was a water vole or rat. Though the two species tend to live in different habitats, there are areas where they overlap, potentially leading to cases of mistaken identity. So how do you tell rats and water voles apart?
How to identify water voles
Scientific name: Arvicola terrestris
Fur: Water vole fur is dark chocolate brown, yellowish on flanks
Size: Male water voles can be up to 20cm long (head and body); tail half the length of a rat’s.
Ears: Small and dark and buried in fur
Nose: Chubby and rounded
Body: Rounded and chunky
Tail: A water vole's tail is furry, thin and hard to see and it's short - less than half the body length
What can I look for on land? The blunt head, brown fur and short, hairy tail that’s hard to see. Their tracks are easy to identify – the forefeet have four toes, while the hindfeet have five.
What can I look for in water? Swims well and dives with a loud ‘plop’ if alarmed.
Any other signs? Substantial piles of droppings at the water’s edge. Voles also eat aquatic vegetation and leave bits lying around. Their burrows are similar to those of rats.
Habitat: Water voles live in and around rivers, ditches, ponds and along urban waterways.
How to identify brown rats
Scientific name: Rattus norvegicus
Fur: Brown rat fur is mainly pale grey-brown; grey-white on flanks and belly
Size: Male brown rats can be up to 50cm long (head and body 25cm, tail about the same).
Ears: Prominent and pale and stick up above head
Body: Long and lean
Tail: A brown rat's tail is scaly, thick and very obviously long - more than half the body length
What can I look for on land? The rat’s prominent ears and long, scaly tail are key identification features.
What can I look for in water? There’s possible confusion here because rats can also swim well. However, unlike water voles, they won’t dive if alarmed.
Any other signs? Groups of oval droppings and burrows with obvious trails
Habitat: Brown rats can be found close to human habitation – around buildings, farmyards, rubbish tips and gardens, also urban waterways.