Suncus murinus - Asian House ShrewMeet the world's largest shrew!...

Meet the world's largest shrew!...NameEtymologyDiagnosisGeographic RangeDescriptionBiologyEcological/Economical ContributionsTaxonavigationSubspecies - Past and PresentType InformationPhylogenyLiterature and ReferencesOther Species Pages

This is not a rat! Photo by W. A. Djatmiko, Wikipedia Commons

NameBinomial: (Linnaeus, 1766) Suncus murinus Synonyms: Up to 59 synonyms are listed by due to its high phenotypic plasticity. Hutterer (2005) Vernacular: Asian House ShrewAlternatives: House Shrew, Asian Musk Shrew, Indian Musk Shrew, Brown Musk Shrew...[ ]more common names

Etymology

The word “shrew” was originally coined to refer to a small mammal. The Old English form of the word was “screawa” or “shrew-mouse”. The other meaning of “shrew” as a "spiteful person" came from the Middle English form “shrewe”, referring to an “evil or scolding person”, arose from then negative perception of the animal, which was believed to have a venomous bite. This was later discovered to be true in some species of shrews. The Asian House Shrew was named as it is commonly found living alongside human habitations (houses) in Asia.ref: Schmidt, 1994

DiagnosisAsian House Shrews and Brown Rats ( ) are both commonly found in Singapore's urban areas, but Asian House Shrews are often Rattus norvegicusmistaken as rats. An Asian House Shrew can generally be differentiated from a rat by its pointed snout, shorter thicker tail and smaller eyes as seen in the pictures below:ref: Wildlife Singapore, 2006

Left: Photo by Ria Tan, . Right: Photo by JC Shou, www.wildsingapore.per.sg www.biopix.com

Asian House Shrews can also be distinguished from the only other species of shrew in Singapore, the Malayan White-toothed Shrew ( )Crocidura malayana, by the bigger size of the former. The Malayan White-tooth Shrew is rare and is restricted to the forests of Bukit Timah Nature Reserve and Central Catachment Nature Reserve.ref: Chua & Lim, 2011

Among the shrew family, the Asian House Shrew is the largest species of shrews. It can be differentiated from its closest relative, the Asian Highland Shrew ( ) by its bigger size, thicker tail and lighter pelage, both dorsal and ventral.Suncus montanus

et alref: Meegaskumbura  ., 2010

Geographic RangeContrary to popular notion, this species is not to Singapore, but is an introduced species. The Asian House Shrew is believed to have originated in  native the forest of central India. With the help of early human transportation both on land and sea, this species then dispersed to surrounding areas, including Africa, Middle East, Southeast Asia and Japan.

et alref: Ellerman, 1961; cited in Meegaskumbura  ., 2010; Global Invasive Species Database, 2006; Corlett, 1992

Red areas show where Asian House Shrews can be found today. Citation: Hutterer, R., S. Molur & L. Heaney, 2008. Suncus murinus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. < >. Downloaded on 03 November 2011.www.iucnredlist.org

DescriptionIn general, the body colour, size and chromosome number varies between localities (between different populations at different areas).

AdultsColour: Light grey in Sri Lanka, grey in Bangladesh, to dark grey in almost all areas of AsiaLength: Head + Body up to 15 cm; tail up to 9.5 cmFace: Small eyes, long pointy snout with conical sharp teeth, long jaws containing rows of pointed teethTail: Thick at the base and hairyWeight of females: 23.5 g to 82.0 gWeight of males: 33.2 g to 147.3 gSexual dimorphism: Males generally larger than females and having well-developed scent glands on the sides of its body (in females this is variable)Chromosome number: Generally 2n = 40; but can range from 2n = 30 or 32 in South India and Sri Lanka to 2n = 35 to 40 in the Malay Peninsula

et al et alref: Chua & Lim, 2011; Kurachi  . and references therein, 2007; Ruedi  . and references therein, 1996.

Tail thick at the base. Photo by Ria Tan. www.wildsingapore.per.sg

Pointy snout and conical sharp teeth. Photo by B. H. Ong. www.wildsingapore.per.sg

YoungAverage litter size: 1.84 gAverage weight of young females: 2.0 gAverage weight of young males: 2.3 gHair: Few guard hairs and well-developed whiskers present when born; underfur develops at day 4, complete fur development by day 10Eyes: Closed eyelids with pink irises at birth, irises turn black at day 2 and eyes open between days 7 to 10Incisors: Full development between days 6 to 14Independency: Self-sufficient by day 20

ref: Dryden, 1968

More information on the anatomy of is detailed in Sharma, 1958. Suncus murinus 

Biology

HabitatAsian House Shrews are commonly found in human habitations, including urban areas. They can also be found in the forest.ref: Global Invasive Species Database, 2006

Life expectancyThey can live for 1.5 to 2 years in captivity and 1 to 2 years in the wild.ref: Schmidt, 1994; Dryden, 1969

Feeding habitsAsian House Shrews are insectivores and eat mainly a wide range of insects. They are also opportunistic feeders and feed on variety of other food items such as plant material, a wide variety of invertebrates such as cockroaches, as well as discarded food items. The Asian House Shrew has a high metabolic rate and are nocturnal and hence requires multiple feeding periods throughout the night.ref: Chua & Lim, 2011; Balakrishnan & Alexander, 1979

ReproductionThe mating system of the Asian House Shrew is unknown. Sexual dimorphism in sizes suggest that they may be polygynous, however as both sexes are known to collect nesting material before the female gives birth, it is suggested that they may be monogamous.

Reproduction occurs throughout the year, peaking during spring and summer. Female Asian House Shrews reach sexual maturity at 35 days old and do not have a behavioral estrus cycle; the process of mating will induce the development of the follicles and start of ovulation. The sperm will spend a long time in the female's reproductive tract before fertilizing the egg.

Nests are constructed in hidden areas called snags using any available resources such as leaves and other loose materials.

Gestation period usually lasts for 30 days. Two litters of 4 to 8 young (usually 3) may be born in one year. The young are weaned at 15 to 20 days old. The young stay in the nest until they are about 75% grown. Should they travel out of the nest however, the young will travel in a convey train with the mother, each clamping its jaws tightly to the rear or base of the tail of the preceding shrew. This caravaning behavior is reported to appear only in very young shrews, initially for the mother to retrieve her straying young back to the safety of the nest. Later on, when the young's eyes are opened, caravaning serves as an environmental exploration.

et alref: Global Invasive Species Database, 2006; Nowak, 1999; Muhammad  ., 1999; Tsuji, 1984

To see how the caravaning behavior looks like (in another species of shrew), check out! this 

Defense mechanismAsian House Shrews have been reported to emit a musky odor to deter predators. The musky odor also discourages other males from following, allowing even distribution of the Asian house shrew population. This musky odor is secreted by the sweat glands on its throat and behind the ears which may also be trapped by the oily secretions of the specialized sebaceous tubules localized in the sideglands to make the odor last. This musky odor also contributes to its alternative common name, Asian Musk Shrew.ref: Dryden, 1967

SoundIt emits a variety of chirps, buzzes or shrill squeaks which may be associated with aggressive behavior. The constant small chattering noises it makes resembles the jingling of coins, and hence is also named as the Money Shrew in China.ref: Chua & Lim, 2011; Burton & Burton, 2002; Nowak, 1999

Conservation statusOwing to its wide distribution and presumed large population, the Asian House Shrew is classified as on the . Least Concern   IUCN Red List

et alref: Hutterer  , 2008

Ecological/Economical Contributions

NegativeDue to its high reproductive rate and low predation risk, Asian House Shrews are a growing ecological threat to many plant and animal species and are considered an invasive species in some countries. Their ability to survive in high densities near human habitations, while damaging foods and other materials has also resulted in them being labelled as pests in some areas. More studies on the management of this species in urban environments are required.ref: Global Invasive Species Database, 2006

PositiveBeing insectivores, Asian House Shrews predate on many insect pest species, such as cockroaches, hence helping to control their population. Asian House Shrews have also been successfully domesticated as a laboratory animal in USA and Japan and is a model species in medicinal, physiology, behavioral and psychology-related research fields.ref: Global Invasive Species Database, 2006; Tsuji, 1999

In our homes - problems and managementIn Singapore, Asian House Shrews are not considered pests, unlike the following commonly-found rodents: Brown Rat ( ), Roof Rat (Rattus norvegicus Rattu

) and House Mice ( ). Asian House Shrews however may be a disturbance for its strong and unpleasant musky odor or its incessant s rattus Mus musculusloud squeaks. They may also destroy stored grain products. Asian House Shrews may also harbor rodent-borne viruses such as leptospirosis but potential for transmission to humans has been poorly documented and probably much lower compared to rats.

Installation of rodent proof structures can exclude shrews, as well as regular mowing of the lawn which decreases their preferred habitat and food(insect) availability. Presence of cats may also reduce their densities, although they seldom eat them. Asian House Shrews can be trapped with mouse traps baited with a mixture of peanut butter and rolled oats. More information on the management of this species can be found . hereref: Rahelinirina, 2010; Global Invasive Species Database, 2006; Schmidt, 1994 and references therein

Warning!The following sections on taxonomy and phylogenetics of the Asian House Shrew may not make for an easy reading, especially if you do not come from a scientific background. Feel free to skip the following sections to the commenting box if you like, or if you feel brave, do read on and gain new knowledge! Brief explanations of each sections are provided in italics. However, it is recommended that you Google or Wiki up any unfamiliar terms.

The following sections would be useful to anyone (with biological knowledge) interested in understanding or researching about the biological history of the Asian House Shrew. In knowing about its and , we would then understand the story of how Asian House Shrews came about  taxonomy   phylogenetic historytoday.

TaxonavigationEvery living-thing on Earth has a name, and is classified systematically into different hierarchical ranks. The following shows the biological classification of the Asian House Shrew.

Animalia (animals)Kingdom: 

Chordata (chordates)Phylum:Subphylum:Vertebrata (vertebrates)

Class:Mammalia (mammals) ....................................................................................................[Linnaeus, 1758]Subclass:Theria .............................................................................................................[Parker and Haswell, 1897]

Infraclass:Eutheria ...............................................................................................[Gill, 1872]Order:Soricomorpha (solendonts, shrews, moles, …) .....................................[Gregory, 1910]

Family:Soricidae (shrews) ..................................................................[G. Fisher, 1814]Subfamily:Crocidurinae (white-toothed shrews) ..........................[Milne-Edwards, 1872]

Genus:Suncus (white-toothed shrews) ..............................[Ehrenberg, 1832]

Species: Suncus murinus (Asian house shrew) .......[Linnaeus, 1766]

(Retrieved on 15 October 2011 from the ) Integrated Taxonomic Information System on-line database

Subspecies - Past and Present

A species can be further differentiated into subspecies, as summarized here for the Asian House Shrew.

Due to its wide morphological variation in body size and tail length, individual populations of Asian House Shrews were classified into different subspecies or races by early mammalogists. Today, most of these subspecies classification have been disregarded as it is currently not possible to have a clear allocation of all listed taxa to subspecies. In 2010, two populations of in Sri Lanka ( and ) were identified as  Suncus murinus  S. m. murinus   S. m. kandianusputative hybrids of and , the closest relative of . However, additional gene comparison studies are  Suncus murinus   Suncus montanus  Suncus murinusrequired to evaluate the extent of hybridization.

et alref: Meegaskumbura  ., 2010; Hutterer, 2005

Type InformationOriginal type descriptions and locality show who first found the organism at where and gave it a name. Specimens collected are then stored at museums so that it will be useful for taxonomists to compare with later collections to confirm that they are of the same species.

Original Type DescriptionFirst described by Linnaeus as . Original description by Linnaeus can be found here: Sorex murinusLinnaeus, C. 1766. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis synonymis, locis

Vol. 1: Regnum Animale, Part 1. Laurentii Salvii, Stockholm 74. Available online .(12th Edition).  .   here

Type LocalityJava, Indonesia.

 is a type species of Genus SuncusSuncus murinus(Ehrenberg, 1832) was described to be the type species of the Genus Suncus. today is classified as a Suncus murinus sacer   Suncus murinus sacer 

subspecies of ; therefore is now considered as a type species of the Genus Suncus. Suncus murinus  Suncus murinus 

The specimen collected by Ehrenberg can be found in the Museum für Naturkunde, Berlin, where Ehrenberg's collections are stored. Its images are as shown:

ref: Dubey, 2007; Hutterer, 2005; Major Flower, 1932; Hemprich & Ehrenberg, 1833

A specimen was collected in Singapore in 1940 and is displayed at the . Raffles Museum of Biodiversity Research (RMBR) 

Specimen at RMBR. Photo by Ivan Kwan. lazy-lizard-tales.blogspot.com

PhylogenyThe phylogeny of the Asian House Shrew is important as from it we can then understand the evolutionary relationships of the Asian House Shrew.

The following two pictures show the phylogenetic relationships between the Asian House Shrews and other shrew species, and the relationships between Asian House Shrews in different geographical locations respectively.

A simplified representation of the phylogenetic tree of the genus Suncus. Only some species are shown here. Note that the Asian Highland Shrew is the sister taxon of the Asian House Shrew (highlighted).

This phylogenetic tree was modified from Figure 2A of the following paper:

Omar, H., E. A. S. Adamson, S. Bhassu, S. M. Goodman, V. Soarimalala, R. Hashim & M. Ruedi, 2011. Phylogenetic relationships of Malayan and Malagasy pygmy shrews of the Genus Suncus (Soricomorpha: Soricidae) inferred from mitochondrial cytochrome B gene sequences. Raffles Bulletin of

(2): 237-243Zoology 59

The relationship among 17 wild Asian House Shrew populations from various locations as indicated in the tree. These populations can be divided into two groups, a and a as shown by the solid black and open bars. The textured bars within the Southeast Asian  South Asian group   Southeast Asian group group indicate the clusters that are closely linked by genetic and geographic relationships.

Although a sample from Singapore was not included in the analysis, Asian House Shrews in Singapore is most likely closely related to the Asian House Shrews in Malaysia due to close proximity between the two countries.

This image was taken from Figure 2 of the following paper:

Kurachi, M., Y. Kawamoto, Y. Tsubota, B. Chau, V. Dang, T. Dorji, Y, Yamamoto, M. M. Nyunt, Y. Maeda, L. Chhum-Phith, T. Namikawa & T. Yamagata., 2007. Phylogeography of wild musk shrew ( ) populations in Asian based on blood protein/enzyme variation. : 543-563Suncus murinus  Biochem Genet 45

Literature and ReferencesBalakrishnan, M. & K. M. Alexander, 1979. Effect of fasting on aspects of feeding on the Indian musk shrew,   (Blyth). Suncus murinus viridescens

  (I3): 178-185.Proc. Indian Acad. Sci. 88Burton, M. & R. Burton, 2002. Musk Shrews. In:  . Marshell Cavendish Corporation. 1709-1710. The international wildlife encyclopedia (3rd Edition)Available online  . (Accessed 14 October 2011)hereChua, A. H. M. & K. P. K. Lim, 2011. Shrews. In: Ng, P. K. L., R. T. Corlett & H. T. W. Tan (eds.), Singapore biodiversity: an encyclopedia of the

. Editions Didier Millet. Raffles Museum of Biodiversity Research, Singapore. 456.natural environment and sustainable developmentCorlett, R. T., 1992. The ecological transformation of Singapore, 1989-1990.    (4): 411-420.Journal of Biogeography 19Dryden, G. L., 1968. Growth and development of   in captivity on Guam.    (1): 51-62.Suncus murinus Journal of Mammalogy 49Dubey, S., N. Salamin, S. D. Ohdachi, P. Barriere & P. Vogel, 2007. Molecular phylogenetics of shrews (Mammalia: Soricidae) reveal timing of transcontinental colonizations.    : 126-137.Molecular Phylogenetics and Evolution 44Global Invasive Species Database (GISD), 2006. " " Available online  . (Accessed 15 October 2010)Suncus murinus hereHemprich, W. & C. G. Ehrenberg, 1833.   5.Symbolae Physicae.Hutterer, R., 2005. Order: Soricomorpha. In: Wilson D. E. & D. M. Reeder (eds.), Mammal species of the world: a taxonomic and geographic

. Available online  . (Accessed 27 October 2011)reference (3rd Edition). John Hopkins University Press hereHutterer, R., S. Molur & L. Heaney, 2008.  . In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. Available Suncus murinusonline  . (Accessed 17 November 2011)hereKurachi, M., Y. Kawamoto, Y. Tsubota, B. Chau, V. Dang, T. Dorji, Y, Yamamoto, M. M. Nyunt, Y. Maeda, L. Chhum-Phith, T. Namikawa & T. Yamagata., 2007. Phylogeography of wild musk shrew ( ) populations in Asian based on blood protein/enzyme variation. Suncus murinus Biochem

  : 543-563Genet 45Linnaeus, C. 1766. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis

 Vol. 1: Regnum Animale, Part 1. Laurentii Salvii, Stockholm  74. Available online  . (Accessed 17 October synonymis, locis (12th Edition). . here2010)Major Flower, S. S., 1932. The recent mammals of Egypt, with a list of the species recorded from that kingdom. Proceedings of the Zoological Society of London  (2): 375-376.102Meegaskumbura, S., M. Meegaskumbura & C. J. Schneider, 2010. Systematic relationships and taxonomy of   and   frSuncus montanus S. murinusom Sri Lanka.    : 473-487.Molecular Phylogenetics and Evolution 55Muhammad, M. U. H., B. M. Azhar, K. A. Ali & M. U. H. Muhammad, 1999. Small mammals inhibiting village households and farmhouses of Central Punjab.    : 207-211.Pakistan Journal of Zoology 30Nowak, R. 1999.  . Baltimore and London: The Johns Hopkins University Press.Walker's Mammals of the World, Sixth EditionOmar, H., E. A. S. Adamson, S. Bhassu, S. M. Goodman, V. Soarimalala, R. Hashim & M. Ruedi, 2011. Phylogenetic relationships of Malayan and Malagasy pygmy shrews of the Genus Suncus (Soricomorpha: Soricidae) inferred from mitochondrial cytochrome B gene sequences. Raffles

  (2): 237-243Bulletin of Zoology 59Rahelinirina, S, A. Leon, R. A. Harstskeerl, N. Sertour, A. Ahmed, C. Raharimanana, E. Ferquel, M. Garnier, L. Chartier, J-M. Duplantier, L. Rahalison & M. Cornet, 2010. First isolation and direct evidence for the existence of large small-mammal reservoirs of   sp. in LeptospiraMadagascar. PLoS One 5(11): e14111. Available online  . (Accessed 8 November 2011)hereReudi, M., C. Courvoisier & P. Vogel, 1996. Genetic differentiation and zoogeography of Asian   (Mammalia: Soricidae). Suncus murinus Biological

  : 307-316.Journal of the Linnean Society 57Schmidt, R. H., 1994. Shrews. In: Hygnstrom, S. E., R. M. Timm & G. E. Larson (eds.),  . University of Prevention and Control of Wildlife DamageNebraska-Lincoln, Nebraska. 87-91. Available online  . (Accessed 8 October 2011)hereSharma, D. R., 1958. Studies on the anatomy of the Indian insectivore,      (3): 427-553.Suncus murinus. Journal of Morphology 102Tsuji K., T. Ishikawa, 1984. Some observations of the caravaning behavior in the musk shrew ( ).    (1/3): 167-183.Suncus murinus Behavior 90Tsuji K., K. Ishii, T. Matsuo & K. Kawano, 1999. The house musk shrew   as a new laboratory animal for use in behavioral studies. Suncus murinus

,  : 1-18.Japanese Journal of Animal Psychology 49Wildlife Singapore, 2006. House Shrew -  . Wildlife Singapore website. Available online  . (Accessed 15 October 2011)Suncus murinus here

Other Species PagesAnimal Diversity Web (//Suncus murinus//)Encyclopedia of Life (//Suncus murinus//)Invasive Species Specialist Groups - ISSG (//Suncus murinus//)

This page was authored by Mei Ailian

Last curated on 2011