68. Pribilof Island Shrew Sorex pribilofensis French: Musaraigne des Pribilof / German: Pribilof-Rotzahnspitzmaus / Spanish: Musarana de Pribilof Other common names: Pribilof Shrew Taxonomy. Sorex pribilofensis Merriam, 1895, “ St. Paul Island, Pribilof Islands, Bering Sea,” Alaska, USA. Sorex pribilofensis is in the S. cinereus group and subgenus Otisorex. It is included in the Beringian clade with S. ugyunak, S. portenkoi, S. jacksomi, S. camtschaticus, and S. leucogaster, although all six species could represent one wide-ranging species based on genetic information. Nevertheless, they are retained as distinct here until addi- tional research is conducted. Sorex pribilofensis has generally been known as S. hydrodromus Dobson, 1889, which has priority; however, the type specimen is from Unalaska Island where no shrews have been recorded recently, indicating that the type locality was in error. The type specimen of S. hydrodromus also had a skull that was more typical of the generally Palearctic S. araneus group. Because of the uncertainty behind the type specimen identity and locality of S. hydrodromus, the name S. pribilofensis is applied to shrews on Pribilof Island. Monotypic. Distribution. St. Paul I, Pribilof Is, off W Alaska, USA. Descriptive notes. Head—body 59-67 mm, tail 31-32 mm, hindfoot 13 mm; weight 4-6 g. The Pribilof Island Shrew is medium-sized, similar to the Barren Ground Shrew (S. ugyunak). Dorsum is grayish brown, and sides and venter are whitish or yellowish white. Tail is relatively short, narrow, and bicolored, being brown above and whitish below. Teeth are dark red. There are five unicuspids,fifth is minute, and first through fourth get slightly smaller from front to back. Habitat. Most common in dune and grass-umbel habitats in maritime tundra, less common in forb and mixed habitats, and absent in upland habitats or areas with large amounts of Carex (Cyperaceae). Food and Feeding. Pribilof Island Shrews primarily eat small soft-bodied invertebrates, and stomach samples have contained remains of beetles. Breeding. No information. Activity patterns. No information. Movements, Home range and Social organization. Pribilof Island Shrews are found at high densities throughout most of the island; population is ¢.10,000 individuals, although additional studies are needed to clarify this. Status and Conservation. Classified as Endangered on The IUCN Red List. Pribilof Island Shrews are restricted to a single island but are found at relatively high densities. They could occur on Unalaska Island, but surveys are needed. There are no impending threats, but as boat traffic increases between the island and the mainland, chances for the Brown Rat (Rattus norvegicus) to be introduced increase. There is also projected development on the island, which could threaten the Pribilof Island Shrew because of the limited available habitat. Bibliography. Byrd & Norvell (1988, 1993), Demboski & Cook (2003), Fay & Sease (1985), Hope et al. (2012), Jackson (1928), Preble (1923), Woodman, Reid & Matson (2008a).

Published as part of Russell A. Mittermeier & Don E. Wilson, 2018, Soricidae, pp. 332-551 in Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona :Lynx Edicions on page 418, DOI: 10.5281/zenodo.6870843