It doesn't often come out in my photos, I don't think, but there's a real difference between baby water voles just out of the nest, and older juveniles/adults. Babies are really quite a dark brown - 70% cocoa solids, I'd say, if you're using chocolate as an indicator. That's how you distinguish them from field voles and bank voles. But older animals are paler-coated, more like a mix of milk and plain chocolate. The photos above show four different young voles, which is reassuring after the heavy rain which can drown new and inexperienced swimmers.