[You must be registered and logged in to see this image.]The pygmy shrew is Ireland’s smallest mammal, with an average lifespan of one year. A big breeding adult may weigh 6g, but they lose weight in winter and their bones shrink so they may end up weighing only 3g during the winter months!
These tiny mammals live in woodlands, hedgerows, farmland, gardens and even bogs. They are common and widespread throughout Ireland.
They are a native species and are believed to have been here at least since the Ice Age, although recent data revealed that they could have accidentally been brought to Ireland from Britain by early human settlers.
An identifying feature of pygmy shrews is their red-tipped teeth, the colour being iron deposits which act as a resistance to wear.
Their diet is composed of various small bugs, beetles, spiders, flies and woodlice, and it has to consume up to 1.25 times its body weight each day in order to survive. This is due to its extremely small size and high metabolic rate.
A period of as little as two hours without food can therefore lead to starvation. They don’t hibernate because, even in winter, they need to keep eating!
Pygmy shrews are solitary creatures and are very aggressive to other shrews. Each one has a separate territory which it defends against all others. Only during the breeding season it is acceptable to cross into another shrew’s territory.
Even though pygmy shrews usually run along tunnels in the undergrowth, they can also climb and even swim if necessary!