Preble's shrew

Preble's shrew
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Eulipotyphla
Family: Soricidae
Genus: Sorex
Species: S. preblei
Binomial name
Sorex preblei
Jackson, 1922
Preble's shrew range

Preble's shrew (Sorex preblei) is a small shrew distributed across the Great Basin of the United States and southern British Columbia in Canada. It belongs to the order Eulipotyphla, family Soricidae and genus Sorex.

Description

The Preble’s shrew has gray pelage on its dorsal side and silvery pelage on the ventral side. Like many other shrews, the Preble’s shrew has a long snout, conspicuous ears, small eyes and plant grade feet. The Preble’s shrew is the smallest member of its genus in North America.[2]

The Preble’s shrew ranges from 77–95 mm in total length, tail length of 28–38 mm, hind feet of 7–11 mm and ear length of 8–11 mm.[3] Besides the relatively small body length, the Preble’s Shrew has several distinctive cranial characteristics. The length of its teeth are typically less than 6.5 millimeters, and the length of mandibular tooth row (C1-M3) are usually found to be less than 4.1 millimeters. The height of the coronoid process has been found to be less than 3.3 millimeters.[4]

Distribution and Habitat

The Preble’s shrew is known to live in Western North America, from the Columbia Plateau to the northern Great Plains. Specimens have been found in northeastern California, northern Nevada,[5] central and eastern Oregon, southeast Washington, western Idaho, all of Montana, western Wyoming, central Colorado and north of the south shores of the Great Salt Lake in Utah.[6] Shrew fossils have even been found as far south as New Mexico.[7] In Canada, the shrew can be found in south-central British Columbia.[8] The Preble’s Shrew typically ranges in elevation from 1280m-2550m.[9]

Most Preble’s shrews live in arid or semiarid shrub-grasses that are associated with coniferous forest dominated by sagebrush. However, these shrews are not restricted to this habitat. They have been found In Oregon living on the big Transition Zone meadows. In another part of Oregon, these shrews have been found in marsh habitats. A majority of Preble's Shrews have been captured in arid habitats, frequently in the immediate or nearby presence of sagebrush. This is likely for protection. Specimens captured in southwestern Wyoming were found in sagebrush-steppe areas: In southern British Columbia, Preble's Shrews were captured in lightly grazed grasslands surrounded by scattered stands of Douglas-fir (Pseudotsuga menziesii) or ponderosa pine.[10]

Life Style and Reproduction

Little is known about the lifestyle of this shrew, but it probably has a similar lifestyle as other shrews in its ecosystem. These other shrews are often active during both the day and night. It is probable that the Preble’s Shrews is active all year. Shrews have been captured in the spring and late summer in southwestern Wyoming [11] and during the summer, fall and spring in British Columbia.[12] In Nevada, these shrews have been collected in the summer and fall.[13] Preble’s Shrews have even been collected in mid-winter in Utah.[14] Collection records from Montana range from mid-February to early November.[15]

The reproductive biology of Preble’s Shrews has not been well studied, and is largely unknown.[16] One study focused on 26 female specimens captured in southeastern Oregon from June and July 1999. Five adult females contained developing embryos: two with 3 embryos, two with 5, and one with 6; mean = 4.4 embryos; All 13 specimens had elongated nipples and extensive mammary tissue, which suggested that each individual had previously produced at least one litter prior to their capture. Four juvenile females exhibited no evidence of reproductive activity. For 16 males, testis size in 15 of the 16 individuals was either less than 2.0 cubic millimeters, signifying that these males were non-reproductive, presumably captured in the year of birth or more than 16.0 cubic millimeters suggesting that they were older and reproductive.; one male with intermediate testis size had little wear on I1, indicating it may have just reached sexual maturity. The data collected in this study suggest that at least two litters were produced prior to the June and July pregnancies.[17]

Ecology

Other small mammal that live in the same ecosystem as the Preble's Shrew include Sorex cinereus, S. haydeni, S. merriami, S. monticolus, S. nanus, and S. vagrans.[18] Preble's Shrews have been collected in Montana in close association with Sorex cinereus, and S. monticolus.[19]

Measurements of population trends, vital statistics and estimates of population density have not been thoroughly studied. At nearly all of the locations where several species of shrews have been captured in association with Preble's Shrew, it is always one of the less abundant species.[20] Predators of Preble's Shrew have not been reported or well documented.

The Preble’s Shrew has been an Animal Candidate Reviewed for Listing as Endangered or Threatened Species twice in recent history, but is currently not listed as an endangered or threatened species.[21] No conservation efforts are currently being undertaken.[22]

Diet

The diet of Preble's Shrew has not been well described, but it likely resembles the diets of other cinereus-group shrews, which feed on small insects and other small invertebrates (worms, molluscs, centipedes, etc.). Its has a relatively low bite force, which suggests that it feeds on soft-bodied prey.[23]

References

  1. ↑ Reichel, J. & Hammerson, G. (2008). "Sorex preblei". IUCN Red List of Threatened Species. Version 2009.2. International Union for Conservation of Nature. Retrieved 8 February 2010.
  2. ↑ Cornely, J. E., L. N. Carraway, and B. J. Verts. 1992. Sorex preblei. Mammalian Species 416: 1-3
  3. ↑ Cornely, J. E., L. N. Carraway, and B. J. Verts. 1992. Sorex preblei. Mammalian Species 416: 1-3
  4. ↑ Junge, J.A. and R.S. Hoffmann. 1981. An annotated key to the long-tailed shrews (genus Sorex) of the United States and Canada, with notes on middle American Sorex. Occasional Papers of the Museum of Natural History, the University of Kansas 94: 1-48.
  5. ↑ Ports, M. A. and S. B. George. 1990. Sorex preblei in the northern Great Basin. Great Basin Naturalist 50: 93-95.
  6. ↑ Long, C. A. and R. S. Hoffmann. 1992. Sorex preblei from the Black Canyon, first record from Colorado. Southwestern Naturalist 37: 318-319.
  7. ↑ Arthur H. Harris and Leslie N. Carraway The Southwestern Naturalist Vol. 38, No. 1 (Mar., 1993), pp. 56-58
  8. ↑ Ports, M. A. and S. B. George. 1990. Sorex preblei in the northern Great Basin. Great Basin Naturalist 50: 93-95.
  9. ↑ Junge, J.A. and R.S. Hoffmann. 1981. An annotated key to the long-tailed shrews (genus Sorex) of the United States and Canada, with notes on middle American Sorex. Occasional Papers of the Museum of Natural History, the University of Kansas 94: 1-48.
  10. ↑ Paul Hendricks and Michael Roedel Northwestern Naturalist Vol. 83, No. 1 (Spring, 2002), pp. 31-34
  11. ↑ Kirkland, G. L., Jr., R. R. Parmenter, and R. E. Skoog. 1997. A five-species assemblage of shrews from the sagebrush-steppe of Wyoming. Journal of Mammalogy 78:83-89.
  12. ↑ Nagorsen, D. W., G. G. E. Scudder, D. J. Huggard, H. Stewart, and N. Panter. 2001. Merriam's shrew, Sorex merriami, and Preble's shrew, Sorex preblei: two new mammals for Canada. Canadian Field-Naturalist 115:1-8.
  13. ↑ Ports, M. A. and S. B. George. 1990. Sorex preblei in the northern Great Basin. Great Basin Naturalist 50: 93-95.
  14. ↑ Tomasi, T. E. and R. S. Hoffmann. 1984. Sorex preblei in Utah and Wyoming. Journal of Mammalogy 65: 708
  15. ↑ Preble's Shrew — Sorex preblei. Montana Field Guide. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. Retrieved on November 16, 2016, from http://FieldGuide.mt.gov/speciesDetail.aspx?elcode=AMABA01030
  16. ↑ Cornely, J. E., L. N. Carraway, and B. J. Verts. 1992. Sorex preblei. Mammalian Species 416: 1-3.
  17. ↑ Carraway, L. N. and B. J. Verts. 1999. Records of reproduction in Sorex preblei. Northwestern Naturalist 80:115-116.
  18. ↑ Ports, M. A. and S. B. George. 1990. Sorex preblei in the northern Great Basin. Great Basin Naturalist 50: 93-95.
  19. ↑ Hendricks, P. and M. Roedel. 2002. Preble's shrew and Great Basin pocket mouse from the Centennial Valley Sandhills of Montana. Northwestern Naturalist 83:31-34.
  20. ↑ Ports, M. A. and S. B. George. 1990. Sorex preblei in the northern Great Basin. Great Basin Naturalist 50: 93-95.
  21. ↑ Preble's Shrew. (2016). Retrieved November 16, 2016, from Environmental Conservation Online System: http://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=A0E6
  22. ↑ Kelly M Cassidya,. C. (2001). Using current protection status to assess conservation priorities. Biological Conservation, Vol 97; 1-20.
  23. ↑ Cornely, J. E., L. N. Carraway, and B. J. Verts. 1992. Sorex preblei. Mammalian Species 416: 1-3.


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