The pygmy shrew is widespread in Europe and arrived in Ireland in the last few thousand years, most likely being brought from Britain by early human settlers. It is very small, being at least half the size of the size of any other shrew found in Ireland. It has one of the highest metabolic rates of any animal and must therefore eat at regular intervals - about every two hours. It has a thick hairy tail and is generally brown with a white underbelly.
Pygmy shrews are aggressively territorial and therefore basically solitary animals. They breed in summer, producing two or three litters of four to seven young, then die before the winter. The pygmy shrew occurs in a wide variety of habitats - sand dunes, upland, farmland and wetland - anywhere there is rich plant cover and a supply of invertebrates.
There have been no detailed studies of the numbers of pygmy shrews in Ireland but it is believed that the population is stable.