American pygmy shrew [1] | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Eulipotyphla |
Family: | Soricidae |
Genus: | Sorex |
Species: | S. hoyi |
Binomial name | |
Sorex hoyi | |
American pygmy shrew range |
The American pygmy shrew (Sorex hoyi) is a small shrew found in Northern Alaska, [4] Canada, and the northern United States, south through the Appalachian Mountains. It was first discovered in 1831 by naturalist William Cane in Georgian Bay, Parry Sound.
This animal is found in northern coniferous and deciduous forests of North America. It is believed to be the second-smallest mammal in the world, but has an extremely large appetite for its size. Due to its fast metabolism, it needs to eat constantly. It digs through moist soils and decaying leaf litter for food.
The American pygmy shrew is the smallest mammal native to North America and is one of the smallest mammals in the world, just slightly larger than the Etruscan shrew of Eurasia. Its body is about 5 cm (2 in) long including a 2-cm-long tail, and it weighs about 2.0 to 4.5 g (0.07 to 0.16 oz). [5] Its pelage is generally a reddish or grayish brown during the summer, and a white-gray color during the winter. The underside is generally a lighter gray. This animal molts about twice a year, once during late summer, and again during the spring. [6] It has a narrow head with a pointed nose, and whiskers. The eyes are small and well hidden. [7] The primary senses used for hunting are hearing and smell.
Sorex hoyi was originally placed in the genus Microsorex, which was a subgenus under Sorex until more research had been done. The American pygmy shrew is in the order Soricomorpha and the family Soricidae. [8] Its two closest relatives are the smokey shrew (S. fumeus) and the large-toothed shrew (S. macrodon).[ citation needed ] This genus is believed to have appeared in the late Miocene. [9]
Pygmy shrews are distributed throughout the boreal areas of North America. This ranges from Northern Alaska, [4] to the Rocky Mountains, through the Great Lakes region, to the Appalachians, to the eastern side of Canada. [7] Although S. hoyi prefers moist habitats, it has been recorded to live in areas with both wet and dry soil, but if it is living in a more arid environment, it needs to have a source of water nearby. [6]
Primarily insectivorous, this animal forages in moist soil and dead leaves to find its prey. Because of the pygmy shrew's small size, its diet primarily consists of insects and insect larvae, while the larger shrews eat insects and worms. [10] Its diet is almost exclusively protein-based. [11] To stay alive, the pygmy shrew has to eat three times its body weight daily, which means capturing prey every 15 to 30 minutes, day and night; a full hour without food means certain death. Because of this high metabolism, the pygmy shrew never sleeps more than a few minutes at a time, as it is in a constant search for food. [5] Although due to its small body size it is always losing body heat, being small has its advantages during the winter when food is scarce. Predators of the American pygmy shrew include hawks, brook trout, owls, snakes, and domestic cats. [12] [13]
Little is known about the reproductive cycle of pygmy shrews. They appear to mate year round, with a bias of births occurring from November through March. [14] The gestation period is estimated to last about 18 days. [7] Females produce a litter of three to eight young, and only give birth once a year. The age the young are weaned is not known with certainty, but by 18 days old, they are nearly full grown, and are usually independent by 25 days. [14] Being mammals, the mother nourishes her young with milk. The maximum lifespan of a pygmy shrew is not known, but it is believed to be about 16–17 months. [14]
Pygmy shrews dig through soil and leaf litter to search for food, and can use tunnel networks created by other animals to aid in that search. They do not sleep or rest for extended periods of times, but alternate between rest and activity all day and night, showing a bias towards nighttime. [11] They have keen senses of smell and hearing to help them find prey. [7] When feeling threatened or scared, the shrews make a sharp squeaking noise and run for cover. Shrews can also swim, which makes them prey to brook trout. Pygmy shrews are in constant motion, and captured shrews have been observed "climbing and walking upside down on the wire top of the cage." [6]
Due to its high metabolism, the pygmy shrew is active year-round and does not engage in any form of torpor or hibernation. Shrews have been known to burrow through snow to find food, showing that winter snow does not stop them. Although usually a positive correlation exists between latitude and shrew body size; the American pygmy shrew is an exception. Although it is constantly losing body heat because it is so small, it also benefits from this because to generate that energy takes less food than it would for a larger shrew. [10]
Shrews are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different families or orders.
The common planigale, also known as the pygmy planigale or the coastal planigale, is one of many small marsupial carnivores known as "marsupial mice" found in Australia. There they fill a similar niche to the insectivores of other parts of the world.
The Etruscan shrew, also known as the Etruscan pygmy shrew or the white-toothed pygmy shrew, is the smallest known extant mammal by mass, weighing only about 1.8 g (0.063 oz) on average.
The northern short-tailed shrew is the largest shrew in the genus Blarina, and occurs in the northeastern region of North America. It is a semifossorial, highly active, and voracious insectivore and is present in a variety of habitats like broadleaved and pine forests among shrubs and hedges as well as grassy river banks. It is notable in that it is one of the few venomous mammals. The specific epithet, brevicauda, is a combination of the Latin brevis and cauda, meaning "short tail".
The cinereus shrew or masked shrew is a small shrew found in Alaska, Canada, and the northern United States. This is the most widely distributed shrew in North America, where it is also known as the common shrew.
The Arctic shrew, also known as the blackback shrew or saddlebacked shrew, is a medium-sized shrew found in Canada and the northern United States. Separate species status has been proposed for the maritime shrew which is found in New Brunswick and Nova Scotia and had been considered to be a subspecies of the Arctic shrew. The tundra shrew was formerly considered to be a subspecies of the Arctic shrew.
The American water shrew or northern water shrew is a shrew found in the nearctic faunal region located throughout the mountain ranges of the northern United States and in Canada and Alaska. The organism resides in semi-aquatic habitats, and is known for being the smallest mammalian diver.
The North American least shrew is one of the smallest mammals, growing to be only up to 3 inches long. It has a long pointed snout and a tail never more than twice the length of its hind foot. The dense fur coat is either grayish-brown or reddish-brown with a white belly. Its fur becomes lighter in the summer and darker in the winter. Although similar in appearance to several species of rodents, all shrews are members of the order Eulipotyphla and should not be mistaken for a member of the order Rodentia. The North American least shrew's eyes are small and its ears are completely concealed within its short fur, giving it very poor eyesight and hearing.
The smoky shrew is a medium-sized North American shrew found in eastern Canada and the northeastern United States and extends further south along the Appalachian Mountains.
The vagrant shrew, also known as the wandering shrew, is a medium-sized North American shrew. At one time, the montane shrew and the Orizaba long-tailed shrew were considered to belong to the same species.
The genus Sorex includes many of the common shrews of Eurasia and North America, and contains at least 142 known species and subspecies. Members of this genus, known as long-tailed shrews, are the only members of the tribe Soricini of the subfamily Soricinae. They have 32 teeth.
Crawford's gray shrew, also known as the desert shrew, is a small shrew found in the southwestern United States and northern Mexico. It is a member of the family Soricidae of the order Eulipotyphla. It was the only known member of the genus Notiosorex until two species, N. villai distributed in Tamaulipas, Mexico, and N. evotis distributed along the northwest coast of Mexico, were named. A fourth distinct species, N. cockrumi, was discovered in Arizona and named in 2004.
The American shrew mole is the smallest species of mole. It is the only living member of the genus Neurotrichus and the tribe Neurotrichini. It is also known as Gibb's shrew mole and least shrew mole. It is not closely related to the Asian shrew mole. The reason that it is called a "shrew mole" instead of being called either a "shrew" or a "mole" is because of its fur, which is a characteristic of shrews and its large head and heavy dentition, which is characteristic of moles.
The Eurasian pygmy shrew, often known simply as the pygmy shrew, is a widespread shrew of the northern Palearctic.
The common shrew, also known as the Eurasian shrew, is the most common shrew, and one of the most common mammals, throughout Northern Europe, including Great Britain, but excluding Ireland. It is 55 to 82 millimetres long and weighs 5 to 12 grams, and has velvety dark brown fur with a pale underside. It is one of the rare venomous mammals. Juvenile shrews have lighter fur until their first moult. The common shrew has small eyes, a pointed, mobile snout and red-tipped teeth. It has a life span of approximately 14 months.
The Eurasian least shrew, also called the lesser pygmy shrew, is the second-smallest mammal by mass after the Etruscan shrew.
The alpine shrew is a species of mammal in the family Soricidae. It is found in the alpine meadows and coniferous forests of central and southern European mountain ranges.
The ornate shrew is a species of mammal in the family Soricidae (shrews). It is endemic to western North America, ranging from Northern California in the United States to Baja California in Mexico. Eight subspecies are known, including the extinct tule shrew, known only from four specimens collected in 1905, and the Suisun ornate shrew, a species of conservation concern in California. Through skull morphology research and genetic testing on Ornate shrew populations, it has been shown that there are three main genetic subdivisions: The Southern, Central and Northern. These three genetic subdivisions of Ornate shrew arose from populations of Ornate shrews getting geographically isolated from other populations.
Preble's shrew is a small shrew distributed across the Great Basin of the United States and southern British Columbia in Canada.
The long-tailed shrew or rock shrew is a small shrew found in Atlantic Canada and the Northeastern United States.