Teeth are key to naming of the shrew

THE list of wild mammals in Ireland has grown by an astonishing amount over the past 100 years. Some of the new additions have here all along but they were animals we never noticed and includes several species of bat.

But there has also been a stream of new arrivals. The latest appears to be a little mammal with a large name — the greater white-toothed shrew. It’s superficially mouse-like, though not remotely related to the mouse. Shrews are insectivores, related to hedgehogs and moles, and have strange snouts, like little elephant trunks. As the names indicate, the greater white-toothed shrew is larger than the pygmy shrew, which is one of our commonest wild mammals, but it’s still not very big. The pygmy shrew has a head and body length (not including the tail) of 45 to 60 mm while the greater white-toothed is 65 to 85 mm.

The white teeth are also significant. There are about a dozen species of shrew in Europe and most of them are very difficult to identify. The key thing is to look at their teeth. I have a zoology book that suggests you can do this with a live shrew by prising its lips apart and examining the teeth with a hand lens. I don’t think it’s as easy as this. Imagine taking a tiny and very cross little mammal with a snout out of a live-trap, managing to prise its lips apart and then getting out your magnifying glass to record the shape, number and colour of teeth that are virtually invisible to the naked eye?