In recent weeks, some visitors to the pond at RSPB Flatford Wildlfe Garden have been treated to a sighting of one of the UK’s most intriguing small mammals – the water shrew. The largest of the three British shrews (the other being the common shrew and the pygmy shrew), the water shrew can grow to a length of 9cm, with a tail of up to 8cm. It has a dark grey or black back, with a white underside. The water shrew doesn’t have webbed feet, but instead stiff hairs on its tail and large hind feet aid swimming in wetland habitats, such as streams, ponds, fens and reedbeds. A water shrew’s thick, water-repellent fur provides protection against the cold and wet.
Adult water shrew Neomys fodiens, Cornwall
Image credit: Katie Nethercoat (rspb-images.com)
Shrews make their homes in small burrows around their watery habitats. Squeezing through these tight burrows can help them shed any excess water from their coats after a swim! They don’t hibernate, staying active throughout the winter. Their breeding season extends from April to September, peaking in May and June. A litter can range from 3 to 15 young and they develop quickly, ready to reproduce the following summer before dying at an age of no more than 19 months.
The main element of their diet is invertebrates – mainly underwater ones such as caddisfly and mayfly larvae. In order to maximise their hunting potential, water shrews have developed some amazing characteristics! Firstly, they can remain active underwater for more than twenty seconds, diving and hunting in even freezing conditions. Scientists have recently discovered that their muscles have evolved to contain particularly high levels of a protein called myoglobin, which stores oxygen, enabling them to stay underwater for longer.
Perhaps even more surprisingly, water shrews have a venomous bite! This is rare amongst mammals. Their saliva contains a poison that subdues their invertebrate prey, and can be strong enough to immobilise frogs and small fish. This superpower gives the little shrew the audacity to tackle prey up to sixty times heavier than itself, including newts, frogs, crustaceans and snails. Certainly a creature not to be messed with!
If you're interested in making a pond in your own garden, advice from the RSPB can be found here. Even a small pond can have huge benefits for wildlife. Who knows, you may even be lucky enough to attract a water shrew!
If you'd like a chance to try to spot a water shrew, Flatford Wildlife Garden is open for just a few more weeks, open every day 10:30-4:30 until 31st October. During half term, there will be A Big Wild Halloween event, where we will be testing your senses! Do you dare to feel inside the boxes to see what is hidden inside? What is that smell hidden in our smelly bags? Families will be able to pick up a Big Wild Halloween activity pack and senses trail from our visitor centre for £3.50, complete with a trail sheet, nature activity booklet, recipe card, character mask and certificate.