Water voles, also sometimes referred to as water rats, are the largest vole species found in the British Isles; they can weigh up to 350 gm.
The water vole's ears are more rounded and it has a blunter nose than a rat. Another distinguishing feature is its furry tail; the rat has a scaly, almost furless tail.
Ratty, of Wind in the Willows fame, was really a water vole. Once they were plentiful in Britain, but in recent years water vole numbers have declined considerably. Habitat loss and predation by mink are thought to have been key factors in this decline, and The Vincent Wildlife Trust has predicted that water voles will be extinct from England and Wales within a few years if nothing is done.
Something is being done, thank goodness. Conservation and habitat restoration work is going on, as part of the National Biodiversity Action Plan, to protect these splendid little creatures. The Environment Agency is the Lead Partner in this work.