I love Jaws, the 1975 movie which sent three men out into the Atlantic on a fishing boat in search of a marauding Great White Shark. There’s another aquatic monster hunting in the ponds and shallow streams of Sussex. But to find a Water Shrew… you’re gonna need a smaller boat.

Water Shrews weigh 15g and measure just 16cm. Unlike other shrews they have an amazing ability to swim and hunt underwater. They’re covered in dense fur – vital insulation against the cold and wet. This sleek wetsuit also traps air bubbles, transforming the shrew into a furry Aero helping it stay buoyant. Powerful, extra hairy hind feet propel this tiny torpedo through the water.

Water Shrews and Great White Sharks have a common feature that sets them apart from their close relatives. They both have a striking demarcation between their dark upperparts and their white underparts. Looking from above, their black backs blend with the pond bottom or seabed. From below, their pale bellies make them invisible in the sunlit water. It’s a submarine survival strategy that helps conceal both hunters and hunted. And the Water Shrew is both.

With sharp, red-tipped fangs, a Water Shrew’s jaws are as fearsome as any shark’s. But the Water Shrew has a trick up its teeth. It’s Britain’s only venomous mammal. When it bites it injects a stupefying saliva which subdues its victims.

In Jaws, the grizzled skipper Quint (Robert Shaw) relates the chilling true tale of the torpedoed WWII cruiser Indianapolis, which sank leaving hundreds of sailors adrift in shark-infested waters. Well, my mate Barry was once bitten by a Water Shrew in Newhaven and his finger went all tingly for about two hours. OK, it doesn’t exactly compare, but the fact that a tiny shrew can make such an impact on a human is pretty impressive.

Slice open a dead shrew’s stomach and rummage inside and you’ll find bits of beetle legs, snail shells, and fishbones. They are relentless, frenetic hunters. If the shrew goes without a meal for more than an hour it will die.

What we are dealing with here is a perfect engine, an eating machine. All this machine does is swim and eat and make little shrews. Between April and September, the mating of the shrew can produce 2-3 litters of 3-15 young. They live a fast, brief life. Few of them will survive for more than a year.

The best way to see a Water Shrew is to sit by a Sussex stream as the sun sets. Bring a couple of friends and some Apricot Brandy, share some tall tales, and wait for a shrew to strike.

By Michael Blencowe: Learning & Engagement Officer, Sussex Wildlife Trust.
Sussex Wildlife Trust is an independent registered charity caring for wildlife and habitats throughout Sussex. It’s easy to join online at: T: 01273 497532 or www.sussexwildlifetrust.org.uk/join

Water Shrew Derek Middleton SussexWildlifeTrust