Eurasian least shrew [1] | |
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Specimen exhibited in the National Museum of Nature and Science, Tokyo, Japan. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Eulipotyphla |
Family: | Soricidae |
Genus: | Sorex |
Species: | S. minutissimus |
Binomial name | |
Sorex minutissimus Zimmermann, 1780 | |
Eurasian least shrew range |
The Eurasian least shrew (Sorex minutissimus), also called the lesser pygmy shrew, is the second-smallest mammal by mass after the Etruscan shrew.
The Eurasian least shrew weighs only 1.2–4 g (0.042–0.141 oz) and has a body less than 4 cm (1.6 in) long, with a 2.5 cm (0.98 in) tail. It has a brown back and a light grey underside, with a fairly clear boundary in between. The color of the back varies seasonally from chocolate brown in summer to light brown in winter. The same bicolor pattern extends to the tail, which has a dark brown tuft of hair at the end. The feet are the same color as the belly, with brown heels.
The Eurasian least shrew inhabits the northern taiga region, and is found throughout Siberia, in northern Europe (Finland, northern Sweden and parts of Norway) and on the islands of Sakhalin and Hokkaidō. It can be found in diverse habitats, including both coniferous and deciduous forests, open fields, and the edges of bogs. The population density appears to be fairly low throughout, though its prevalence may be underestimated in surveys since its small size lets it escape many commonly used traps.
Due to its small size and reclusive habits, the Eurasian least shrew can be difficult to spot. Like shrews in general, the Eurasian least shrew mainly eats insects, but will also dine on carrion or any other source of protein it finds. In winter, it may occasionally seek food indoors. Because of its small size for a mammal, the Eurasian least shrew has an extremely high metabolic rate and must eat frequently to avoid starvation; in captivity it has been reported to eat 120 meals a day, consuming three to four times its own weight each day. The Eurasian least shrew is active around the clock, with occasional sleep periods of 10–50 minutes each.
The Eurasian least shrew can swim well, and in captivity even seems to enjoy playing in water. Its small size also makes the Eurasian least shrew a phenomenal climber: it has been observed climbing up even the smooth inside corner of a glass terrarium. Its eyesight is poor, but it has very good hearing. While the Eurasian least shrew frequently emits sounds, much of its communication is in frequencies beyond the limits of human hearing.
The female Eurasian least shrew has one or two litters a year, each typically consisting of 3–6 offspring. Little is known about the typical lifetime of the Eurasian least shrew in the wild, but in captivity some have managed to reach an age of over 2.5 years.
The Eurasian least shrew may be mistaken for the slightly larger Eurasian pygmy shrew (S. minutus), which is commonly found in the same areas. Besides the size difference, the two species may be distinguished by the tail and feet of the least shrew being noticeably shorter in proportion to its body.
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 red-toothed shrews of the subfamily Soricinae are one of three living subfamilies of shrews, along with Crocidurinae and Myosoricinae. In addition, the family contains the extinct subfamilies Limnoecinae, Crocidosoricinae, Allosoricinae and Heterosoricinae. These species are typically found in North America, northern South America, Europe and northern Asia. The enamel of the tips of their teeth is reddish due to iron pigment. The iron deposits serve to harden the enamel and are concentrated in those parts of the teeth most subject to wear. Members of the genera Chimarrogale, Nectogale, Neomys (Nectogalini) and some members of Sorex (Soricini) are known as water shrews, due to having a semi-aquatic lifestyle.
The American pygmy shrew is a small shrew found in Northern Alaska, 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.
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 marsh shrew, also known as the Pacific water shrew, Bendire's water shrew, Bendire's shrew and Jesus shrew is the largest North American member of the genus Sorex. Primarily covered in dark-brown fur, it is found near aquatic habitats along the Pacific coast from southern British Columbia to northern California. With air trapped in its fur for buoyancy, marsh shrews can run for three to five seconds on top of the water. It measures about 16 cm (6.3 in) in length, including a 7-centimetre (2.8 in)-long tail, and weighs an average of 14.5–16 g (0.51–0.56 oz). The marsh shrew's diet consists mainly of invertebrates, which it hunts on land and in the water. They are rare; their populations are thought to be in decline, and they are considered endangered in parts of their range.
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.
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.
Laxmann's shrew, or the masked shrew, is a species of shrew. Its range extends from northern Scandinavia and the Baltic to the Sea of Japan, including Hokkaidō, Sakhalin, and the Korean Peninsula. It favours mountain forests but is sometimes found in tundra and moorland, and also in lowland areas as well. It avoids cultivated land.
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 Azumi shrew is a species of mammal in the family Soricidae. It is endemic to Japan, where it is found in the mountainous regions of central Honshu Island. It is a close relative of the Eurasian least shrew. It is threatened by habitat loss.