Posted on 22/05/2019
The water shrew is widespread in the UK, and exactly the kind of semi-aquatic creature that thrives on our network, but it’s not an easy animal to get to know. You need to have your eye in. It’s small, and hyperactive, and spends a fair bit of time under water. It doesn’t even particularly like the company of its own kind, so it’s not usually going to hang around and let us watch it. I got lucky though, when a water shrew decided to take up residence in my back garden.
I made my own luck, you might say, by installing ponds, including one using an old iron bath, that I sunk into the border by the lawn. It was my neighbour who first alerted me to the possibility of a water shrew was present among us. One or two of her quite large goldfish had been found dead, with mysterious injuries. She had glimpsed something small, acting suspiciously.
Notwithstanding the size of the victims, I did think it feasible that the culprit was a water shrew. Not long after, one early morning, I saw it. From the corner of my eye I caught sight of movement in the water and across the rim of the bath. I waited a while, quietly and keeping still. I was rewarded for my patience when the shrew reappeared and slipped swiftly under water, a silvery submarine among the pondweed, causing considerable turbulence as it foraged.
I noted how this shroud of bubbles kept it dry, and made it so buoyant that it had to cling to the weed and paddle like mad to stay under. When it ran out of breath, it popped out of the water onto the rim of the bath like reversed footage of a shrew jumping in.
Water shrews are strange and marvellous creatures. They have black glossy fur above, contrasting with their ivory white fur underneath. They are quite large, for a shrew, and typically hyperactive. They have to keep eating, and don’t hibernate. They also come armed, having toxic saliva with which they debilitate larger prey. They are literally red in tooth, as well. They have long, tactile whiskers for detecting prey underwater, and can eat half their own body weight every day – which isn’t a lot of weight, but is a lot of beasties. They also have closable nostrils and a long tail for steering. Quite remarkable animals, all round.
I had a number of other encounters with my shrew, and wrote an essay about it – titled Shrewdunnit – which became the title of a book I had published, compiling my nature notes as a diary through the calendar year. We can’t be sure the shrew was responsible for the death of Phyllis’s goldfish, by the way. The case is still unsolved.
I was reacquainted with the water shrew – not the water shrew (they may have action-packed lives but these tend to be very short) – when one took up residence for a couple of days in an ornamental pond at the RSPB’s headquarters while I was working there. What was odd about this is how unfazed the shrew seemed by the presence of onlookers, so absorbed in its own world of pond foraging. And why was it that for the two days it was there – bold as brass, so visible and obvious – and then the next day gone? There were no reports of water shrew at that pond for several years after until one did exactly the same thing a few years later – it entertained the troops for a couple of days in exactly the same spot, before disappearing again.
Water shrews use our waterway network to travel to new (usually watery) locations, sometimes branching out to find new habitats, which don’t always have to be wet. I had another encounter with one, nowhere near water, in a local wood. I could hear it scuttling among the dry twigs and leaf litter. Again, it was curiously obvious as it went studiously about its business.
It’s also strange how often you find shrews dead on footpaths, often apparently unmarked. It could be that they are dropped by predators, which can find them distasteful to eat. Or it may be that their high octane lifestyles see them keel over, mid-scuttle, when their time’s up. We actually have four other shrew species in the UK – the common, pygmy, greater white toothed and lesser white toothed. The first two are much smaller and browner than the water shrew, while the latter two are only found in isolated populations in the Channel Islands and Isles of Scilly.
Relaxing beside our canals and rivers might present your best chance of getting acquainted with this slightly improbable creature. My advice is to be alert for signs, and patient in any subsequent investigations. They water shrew is always busy. It’s mysterious that our paths don’t cross more often. Perhaps we just need to look more closely.