Sorex cinereus (Kerr, 1792)
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publication ID |
https://doi.org/ 10.5281/zenodo.6870843 |
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DOI |
https://doi.org/10.5281/zenodo.6869708 |
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persistent identifier |
https://treatment.plazi.org/id/3D474A54-A03E-8753-FAF3-A3EF1BFFFA43 |
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treatment provided by |
Felipe |
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scientific name |
Sorex cinereus |
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Masked Shrew
French: Musaraigne cendrée / German: Amerikanische Maskenspitzmaus / Spanish: Musarana ceniza
Other common names: Cinereus Shrew, Common Shrew
Taxonomy. Sorex arcticus cinereus Kerr, 1792 View in CoL ,
Fort Severn , Ontario, Canada.
Sorex cinereus is in the S. cinereus group and subgenus Otisorex. The S. cinereus group contains S. rohweri, S. longirostris , S. cinereus , S. fontinalis , S. lyelli , S. emarginatus , S. millet, S. preblei , S. hayden , S. pribilofensis , S. ugyunak , S. portenkoi , S. jacksoni , S. camtschaticus, and S. leucogaster . S. fontinalis has generally been considered a subspecies of S. cinereus but is considered a separate species here because the two species apparently overlap in distribution in Pennsylvania without interbreeding, although genetic data are needed to supportits species status. Recently, some Pacific Northwest populations have been described as a new species, S. rohweri, based on morphometric and genetic data. Sorex longipilis and S. milleri are included in S. cinereus genetically, but S. cinereus might represent multiple species. Recent genetic data have found various clades in S. cinereus from the Midwest, West, Southwest, Southeast, and East; S. longirostris being closest to the East clade; and S. milleri being closest to the Midwest clade. Sorex miller: might represent a relict population of S. cinereus , although morphometric data show that S. milleriis distinct; additional research is needed. Morphological data placed S. cinereus close to S. haydeni and S. fontinalis , although genetic data have not supported this. Two populations from south-western USA were closer to various other species, one from the central Rocky Mountains being closer to S. lyelli and the Beringian clade, while the other from northern Arizona and New Mexico was closer to S. haydeni and S. preblei . Subspecies acadicus is now considered a junior synonym of nominotypical cinereus based on recent morphometric studies. Subspecies here do not currently represent distributions of major clades in S. cinereus . Seven subspecies recognized.
Subspecies and Distribution.
S.c.cinereusKerr,1792—N&EAlaskaE&SthroughmuchofCanada(includingNewfoundland,NovaS.c.,andPrinceEdwardI)intothecontinentalUSAasfarSas NCNewMexicoandNGeorgia.
S. c. hollister: H. H. T. Jackson, 1925 —-W & C Alaska (USA).
S.c.lesueuriiDuvernoy,1842—NIllinoisEtotheSportionofMichiganandStoS Indiana(NEUSA).
S.c.miscixBangs,1899—LabradorandNEQuebec(ECanada).
S.c.magriculusGreen,1932—SNewJersey(NEUSA).
S.c.ohionensisBole&Moulthrop,1942—N&CMichigan,Ohio,andEPennsylvania(NEUSA).
S. c. streatori Merriam, 1895 — SE Alaska to SW British Columbia along the full Pacific coast of W Canada. View Figure
Descriptive notes. Head-body 42-67 mm, tail 29-50 mm, hindfoot 10-5-13 mm; weight 2-5-6 g. The Masked Shrew is relatively small, similar to the South-eastern Shrew ( S. longirostris ) and the Maryland Shrew ( S. fontinalis ). Dorsum is dark brown, sometimes with darker dorsal line and paler sides, and their entire body is grayer in winter. Venter is distinctly paler than dorsum, being grayish brown with silvery tinge. Tail is c.65-80% of head-body length, narrow, and distinctly bicolored, being dark brown above and nearly white below; tip has distinct black tuft of hair 2-3 mm long, unlike the Prairie Shrew ( S. haydeni ) that has brown tip on tail. There are five unicuspids,first four are approximately the same size, becoming slightly smaller from first to fourth, and fifth is significantly smaller butstill visible in tooth row; some individuals have a third unicuspid that is smaller than fourth, especially in subspecies ohionensis. Teeth are pigmented dark red, being darker than that of the South-eastern Shrew. Chromosomal complement has 2n = 66 and FN = 70.
Habitat. Wide variety of habitats including arid grasslands, woodlands, marshlands, and tundra. The Masked Shrew is a habitat generalist in temperate and polar regions and is often one of the most common shrews and small mammals in an area. Although Masked Shrews can be found in more arid habitats, they often require areas with moisture and are captured at highest densities in grass-sedge marshes, willow-alder fens, heath moss bogs, various swamp habitats, and some shrublands and prairies and are less common in xeric and tundra habitats although they are still present. When sympatric with the Prairie Shrew, Masked Shrews stay more in forested and woodland habitats, and Prairie Shrews stay in open grassland habitats.
Food and Feeding. Masked Shrews feed often and voraciously like most other species of shrews, only being able to survive for a few hours without food because of their high metabolic rate. A captive individual (3-6 g in weight) feeding on liver ate c.11-7 g of food/day over a seven-day period, which indicated that c.3-3 times their own body weight must be eaten each day. Otherstudies with captive individuals feeding on liver found values of 1-3-3-8 g/day, indicating that they more often eat about their weight in food. Masked Shrews eat various small invertebrates and vertebrates, including adult and larval insects, centipedes,snails, slugs, worms, sowbugs, spiders, harvestmen, salamanders, possibly carrion, seeds on occasion, and small amounts of Endogone fungus. Based on data from the eastern USA and Nova Scotia, beetles and various insect larvae usually made up the largest proportion of diets of Masked Shrews (65-3%), while small vertebrates (including salamanders; 7-1%), centipedes (6-8%) worms (4-3%), mollusks (1-4%), and sowbugs (12%) made up smaller proportions of diets. Many insect larvae are eaten, especially beetles, moths, and flies, although adult forms of insects are also eaten on occasion, especially beetles. Earthworms do not make up a very significant proportion of their diets, indicating foraging is more epigeal than hypogeal because their diets consist largely of epigeal prey (e.g. beetles). Nevertheless, captive individuals are known to investigate small holes and burrows and will pull worms out if they are found. When foraging, Masked Shrews generally rummage through leaf litter and vegetation, often disappearing under the cover. Food is occasionally cached in side compartments in tunnels.
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Breeding. Breeding of Masked Shrews primarily occurs in March-September, although there have been reports of births throughout the year including mid-winter in Nova Scotia. Pregnant females have been reported from early April until August. Females can breed 1-6 times/season, which is abnormally high for shrews, and some young can breed in the same season they are born, although they more often breed the following year. Gestation lasts c.18 days, and litters generally have 2-10 young (average 6-7 young but 4-9 in some regions). Newborns average 0-28 g and are 12-14 mm from crown to rump. Young are weaned at c.3 weeks, and sexual maturity is reached at ¢.20-26 days old, looking adult-like at c.20 days old and leaving the nest at ¢.27 days old. Caravanning has been observed after young are able to leave the nest, althoughit only lasts c.5 days. Young adults often start appearing outside the nest in June and stop appearing in about September, although there are reports from before June and after September. Masked Shrews generally do not live longer than 19 months, although some individuals have been reported to live up to 30 months, surviving for two breed-Ing seasons.
Activity patterns. Activity of Masked Shrews occurs day and night in short bouts of foraging and other activity, with longer periods of rest between them; they are usually most active throughout the night. During rest periods, their metabolic rate is depressed, and they often sleep. They are also most active during moist weather and with increased cloud cover and rain. Nests are generally found under rotten logs, rocks, or human structures and consist of balls of woven dry grass ¢.4—6 cm in diameter, with openings c¢.2-3 cm in diameter. Leaves and plastic have been used to line nests, and there are often exit tunnels attached to the nest.
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Mount Lyell Shrew
Movements, Home range and Social organization. Masked Shrews use aboveground runways and narrow underground tunnels (c.2 cm in diameter) to get around and will excavate their own tunnels or use tunnels created by other small mammals. They are territorial and generally solitary when not breeding or rearing young, although four adult individuals have been found sharing a tunnel system, indicating that they might be somewhat gregarious in winter and during breeding. Males generally abandon their home ranges during breeding to travel and find females, and females retain and expand their home ranges. Home ranges generally decrease in size as density increases. Densities vary throughout the year and by location ranging from 2-5-27 ind/ ha in Ohio (7-6-10 ind/ha in white cedar and black spruce forests) and 2-13 ind/ ha in Pennsylvania. In a seven-year study, densities were 1-23 ind/ha in south-eastern Manitoba, being lowest in spring and highest in late summer/early autumn, correlated with when juveniles/subadults enter the population. Mortality rates are high: c.80% of young die before reaching sexual maturity, and ¢.50% of the surviving shrews die during the next five months. At high densities, some individuals call to each other, then meet to have a short territorial dispute before running away from each other and then calling again after several minutes. These calls have been observed over relatively large areas of c.900 m?. Like most temperate species of shrews, body mass decreases during winter and rapidly increases in spring.
Status and Conservation. Classified as Least Concern on The IUCN Red List. The Masked Shrew has a very wide distribution and faces no major threats, being able to survive in highly disturbed habitats. Fossil record shows that it once occurred as far south as north-eastern Mexico. It is one of the most common species of small mammals throughout its distribution and is common around agricultural settlements and even some urban areas. Effects of the bacterial insecticide Bacillus thuringiensis have been noted for the Masked Shrew; when it is used, males in a population decreased due to emigration, but they were not negatively affected by the application.
Bibliography. Anderson (1981), Bellocq & Smith (1994), Bellocq et al. (1992), Blossom (1932), Brown (1967), Cassola (20161), Demboski & Cook (2003), Forsyth (1976), French (1984), George (1988), Hope et al. (2012), Innes et al. (1990), Ivanitskaya & Kozlovsky (1985), Kirkland (1976, 1977a, 1977b), Merritt (1995), Moore (1949), Morrison et al. (1959), Pruitt (1954), Stewart et al. (1993), Vickery & Bider (1978), Whitaker (2004), Whitaker & Schmeltz (1973), Woodman (2018), van Zyll de Jong (1980), van Zyll de Jong & Kirkland (1989).
Maryland Shrew
French: Musaraigne du Maryland / German: Maryland-Spitzmaus / Spanish: Musarana de Maryland
Other common names: Eastern Shrew
Taxonomy. Sorex fontinalis Hollister, 1911 View in CoL ,
“ Cold Spring Swamp , near Beltsville [Prince George Co.], Maryland,” USA.
Sorex fontinalis is in the S. cinereus group and subgenus Otisorex. Sorex fontinalis has variously been included in S. cinereus as a subspecies, although it does seem to over-lap in distribution without interbreeding. Morphologically, S. fontinalis is nearly identical to S. cinereus , and genetic data are needed to determine if S. fontinalis is really a distinct species or a subspecies of S. cinereus . Sorex fontinalis could be hybrid between S. cinereus and S. longirostris , although this has not been studied. Sorex fontinalis is retained as a distinct species here due to uncertain taxonomic relationships. Monotypic.
Distribution. SE Pennsylvania, extreme W New Jersey, NE West Virginia, N Maryland and N Delaware (NE USA). View Figure
Descriptive notes. Head—body 51-58 mm, tail 27-39 mm, hindfoot 10-13 mm; weight 2:3-4-5 g. The Maryland Shrew is small, externally similar to the Masked Shrew (S. ¢inereus), but it is significantly smaller with shortertail, shorter skull, shorter and broader rostrum, and shorter unicuspid tooth row, making it somewhat more similar to the South-eastern Shrew ( S. longirostris ). Dorsum of the Maryland Shrew is dark brown, and venteris significantly lighter grayish brown. Tail is relatively short compared with related species (c.65% of head-body length), narrow, and distinctly bicolored, being dark brown above and lighter below. Teeth are pigmented dark red. There are five unicuspids,first four are about the same size, becoming slightly smaller from first to fourth, and fifth is significantly smaller but still visible in tooth row.
Habitat. Mature lowland forest, mid-slope oak forest, ridge oak and black gum forest, and oak regrowth from clearing. The Maryland Shrew has also been collected in meadows, hedgerows, and other forest types.
Food and Feeding. No information.
Breeding. No information.
Activity patterns. No information.
Movements, Home range and Social organization. No information.
Status and Conservation. Not assessed on The IUCN Red List. The Maryland Shrew has a very small distribution, and there is uncertainty about whetherit should be recognized as a species or not. Additional research is needed to thoroughly assess its conservation status, although it seems to be tolerant to human activity.
Bibliography. George (1988), Kirkland (1977a, 1985), Whitaker & Hamilton (1998), van Zyll de Jong & Kirkland (1989).
French: Musaraigne du Lyell / German: Mount-Lyell-Spitzmaus / Spanish: Musarana de Monte Lyell
Other common names: Lyell Shrew
Taxonomy. Sorex tenellus lyelli Merriam, 1902 View in CoL ,
“ Mt. Lyell , Tuolumne Co., Califonia,” USA.
Sorex lyelli is in the S. cinereus group and subgenus Ofisorex; it is closest to a population of S. cinereus from the central Rocky Mountains that might represent a distinct species and the Beringian clade. Monotypic.
Distribution. EC Sierra Nevada, EC California (WC USA). View Figure
Descriptive notes. Head-body 50-68 mm, tail 39-44 mm, hindfoot 11-12 mm; is 4-6 g. The Mount Lyell Shrew is relatively small. Dorsum is pale grayish brown,sides are gray, and venter is grayish white. Feet are whitish. Tail is ¢.60-80% of head-body length, narrow, and distinctly bicolored, being pale grayish brown above and whiter below. Teeth are pigmented dark red. There are five unicuspids,fifth is minute, and third is larger than fourth.
Habitat. Montane dry sagebrush steppe and wetlands at elevations of 2100-3630 m.
Food and Feeding. No information.
Breeding. No information.
Activity patterns. No information.
Movements, Home range and Social organization. No information.
Status and Conservation. Classified as Least Concern on The IUCN Red List. The Mount Lyell Shrew has a restricted distribution in and surrounding Yosemite National Park. Its habitat is rather remote and unaltered by humans, and it seems to be relatively common in its small distribution.
Bibliography. Demboski & Cook (2003), Epanchin & Engilis (2009), Grinnell (1933), Hope et al. (2012), Nature-Serve (2017), Williams (1984).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
