Arctic shrews are medium-sized shrews with cylindrical bodies. The head is long with a pointed nose, like other shrews. The hair is short and soft, the eyes and ear pinnae are all very small, and the tail is long. (Baker, 1983; Kirkland and Schmidt, 1996)
The mass of (Clough, 1963)ranges from 5.3 to 13.5 g. Total length ranges from 100 to 125 mm. Tail length ranges from 36 to 45 mm. The hind foot length ranges from 12 to 15 mm.
Arctic shrews show slight seasonal variation in pelage. Tri-color bands are more distinct during the winter months, from October to June. Like others in the genus Sorex, arctic shrews molt twice a year. Winter fur is thicker and brighter. Summer fur is less insulative and paler. Also, the banded fur pattern is less developed in juveniles. (Baker, 1983; Clough, 1963)
The dental formula for Sorex is I 3/1, C 1/1, P 3/1, M 3/3, with thirty-two teeth total. Teeth have a brownish-red pigment on the tips. , like other Sorex, possesses unicuspid teeth after the canines. Arctic shrews have four unicuspids; the first two unicuspids are large and equal in size, and the third is smaller than the first two, but larger than the fourth. (Baker, 1983; Kirkland and Schmidt, 1996)
In Wisconsin, the breeding season is from February to August. The breeding season is shorter in more northern areas, from April to August. Arctic shrew females give birth to 1 or 2 litters each year. Litter sizes range from 4 to 10 offspring, with an average of 7 offspring per litter. The gestation period ranges between 13 and 21 days. The lactation period ranges between 20 and 24 days. The time from conception to weaning lasts between 5 and 6.5 weeks. Both female and male arctic shrews reach sexual maturity after one year. (Baird, et al., 1983; Baker, 1983; Clough, 1963)
Newborn arctic shrews are helpless. They remain with and are cared for by their mother until the end of the weaning period. The young stay with their mother until 5 to 6.5 weeks after conception. Males play no role in parental care. (Kirkland and Schmidt, 1996)
In the wild, individual arctic shrews can live as long as 18 months. The juvenile mortality rate is approximately 50% during the first month. (Buckner, 1966)
Arctic shrews are active during day and night. There are contradicting reports on levels and cycles of activity throughout the day. One claim is that they are least active between 0600 h and 1000 h, while another reports alternating periods of activity and rest, with an average of fourteen periods of activity daily. (Buckner, 1964; Clough, 1963; Kirkland and Schmidt, 1996)
Arctic shrews are very active and move quickly. Periods of inactivity are spent lying on the ground, either on one side or with the ventral side down, body rolled up, and head tucked under the body. Grooming consists ofwiping the forefeet rapidly along the mouth. (Clough, 1963)
Arctic shrews spend most of their time alone. Two arctic shrews cannot live together in a cage in laboratories, since one always dies. The cause of this is unclear, since the dead shrew has not been injured or bitten. (Clough, 1963)
No information is available specifically for (Baron, et al., 1983), but in general, olfaction is the strongest and most developed sense in shrews. A large portion of a shrew's brain is devoted to olfaction.
Shrews lack fully ossified auditory bullae, but they can produce and perceive sounds in high frequencies. Calls are made for defense and courtship, and calls are also made because of fright. (Branis and Burda, 1994; Hutterer, 1985)
Touch is probably important to shrews. Mothers touch their young, and mates touch each other.
Arctic shrews are insectivorous. Larch sawflies make up a large proportion of the diet. Arctic shrews also eat grasshoppers such as redlegged grasshoppers. Generally, they feed on insect larvae, pupae, and adults, and occasionally other invertebrates. Aquatic insects are also consumed, since arctic shrews sometimes reside near streams and bog banks. In captivity, arctic shrews consume dead voles, fly pupae, and mealworms. (Buckner, 1970; Kurta, 1998)
Melanoplus ferumrubrum grasshoppers by climbing approximately 31 cm and pouncing on the prey, seizing it with jaws and feet. (Baker, 1983; Jackson, 1961; Kirkland and Schmidt, 1996; Baker, 1983; Buckner, 1970; Jackson, 1961; Kirkland and Schmidt, 1996)usually forages on the ground, but will also climb plants. Arctic shrews exhibit hunting behavior, preying on grasshoppers. has been observed to attack adult
A defense strategy of arctic shrews is excreting a musky scent from its flank glands, a strategy also used in other shrew species. Arctic shrews also remain under cover most of the time and are colored in a waywhich helps to hide them. (Baker, 1983)
Arctic shrews may have a role in regulating insect pest populations.
masked shrews, meadow voles, and northern short-tailed shrews. Other small mammal species that share habitats with arctic shrews are water shrews, pygmy shrews, deer mice, southern red-backed voles, heather voles, southern bog lemmings, meadow jumping mice, ermines, eastern chipmunks, least chipmunks, and red squirrels. (Kirkland and Schmidt, 1996)associates with many other small mammals. The most common and frequent ecological associations occur with
Arctic shrews are susceptible to various ectoparasites. These include hypopial mites (Labidophorus soricis), larval ticks (Ixodes muris), myobiid mites (Proomyobia breviseosus and Amorphacarus elongatus), laelapid mites (Androlaelops fahrenholzi), ixodid ticks (Haemaphysalis leporispalustris and Ixodes murinus), Parasitoidea ticks (Euhaemogamasus liponyssoides and Monyssus jamesoni), trombiculid mites (Trombicula harperi) and other Trombicula, myobid mites (Amorphacarus henegerorum), pyemotid mites in the genus Resinacaris, and fleas (Corrodopsylla curvata). (Lawrence, et al., 1965; Whitaker and Pascal, 1971)
There are no known positive effects ofon humans.
There are no known adverse affects ofon humans.
Arctic shrews are abundant in suitable habitats throughout their range.
There are three subspecies of S. a. arcticus, S. a. laricorum, and S. a. maritimensis. (Kirkland and Schmidt, 1996):
During the Pleistocene, arctic shrews occurred farther south than they do today. The present range of arctic shrew populations was covered by ice during the Pleistocene. Most arctic shrew fossil records are from Pleistocene deposits from the central and southern Appalachian Mountains, and from the Great Plains. Earliest records are from Colorado and Virginia, from the Late Irvingtonian, between 690,000 to 900,000 years before present. (Kirkland and Schmidt, 1996)
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Nancy Shefferly (editor), Animal Diversity Web.
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living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
uses sound to communicate
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.
an animal that mainly eats meat
flesh of dead animals.
uses smells or other chemicals to communicate
active at dawn and dusk
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
union of egg and spermatozoan
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
marshes are wetland areas often dominated by grasses and reeds.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
chemicals released into air or water that are detected by and responded to by other animals of the same species
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
uses touch to communicate
Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
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