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Chimarrogale himalayicaHimalayan water shrew

By Kirsten Solmundson

Geographic Range

The Himalayan water shrew (Chimarrogale himalayica) has a wide but sporadic distribution across the Himalayas, including: Northern India, Nepal, Laos, Myanmar, Vietnam, southern China, and Taiwan. This species is sometimes confused with other water shrew species, such as the Japanese water shrew (Chimarrogale platycephalus) and the elegant water shrew (Nectogale elegans), due to similar habitats, appearances, and taxonomy. Three subspecies have been distinguished within C. himalayica: C. h. himalayica found in the Himalayas; C. h. varennei found in Myanmar, Yunnan, China, Laos, and Vietnam; and C. h. leander found in Fujian, China and Taiwan. (Yuan, et al., 2013)

Habitat

This semi-aquatic species is associated with clear, swift-flowing streams in forested mountainous regions. Himalayan water shrew can be found in lowland habitats at elevations of 220-250 m, and in pre-montane conifer/broad-leafed evergreen forests with an elevation range of 250-1270 m, although specimens have been collected at elevations as high as 3048 m. The depth range of this species is unknown but previous capture efforts focused on a 0.5 m deep stream. The wide distribution of Himalayan water shrew is attributed to a broad adaptive capacity and dispersal ability that is associated with an aquatic lifestyle. (He, et al., 2010; Jenkins, 2013; Lunde and Musser, 2002)

  • Aquatic Biomes
  • rivers and streams
  • Range elevation
    220 to 3048 m
    721.78 to 10000.00 ft
  • Average depth
    0.5 m
    1.64 ft

Physical Description

Himalayan water shrew are small, semiaquatic mammal. Few individuals have been captured. Those few possessed a head-body length range of 111 - 132 mm, with an average of 121 mm, and a tail length of 79 - 88 mm, with an average of 85 mm. The tail is slender but densely haired. Adult Himalayan water shrews weigh between 37 - 56 g. There is no sexual dimorphism in appearance or size. Pelage is flat and dense, and grey-brown in colour with no dorsal-ventral colour boundaries. Skull and facial features include: relatively flat snout, small pinnae, and long, brown whiskers, and the brain cavity volume is large in comparison to other shrews. The greatest length of skull is between 25 – 28 millimeters, possessing 3 upper unicuspid teeth (upper incisors lack cusps). (Francis, 2008; Li and Boren, 1999; Lunde and Musser, 2002; Sterndale, 1884)

This shrew is historically placed in the subfamily Crocidurinae based on presence of white tipped teeth. However, ultraviolet rays have revealed red coloured teeth tips, and karyotyping evidence has suggested this shrew be placed in subfamily Soricinae. There are three recognized subspecies of C. himalayica, as previously mentioned, but new evidence strongly supports these subspecies as paraphyletic, and suggests they should be considered as individual species. (Mōri, et al., 1991; Yuan, et al., 2013)

Metabolic rates have not been quantified but are known to be particularly high within aquatic soricines; this high metabolic rate is thought to be an adaptation for the high-energy expenditure associated with diving and foraging in cold water. (He, et al., 2010)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    37 to 56 g
    1.30 to 1.97 oz
  • Range length
    190 to 220 mm
    7.48 to 8.66 in

Reproduction

Little is known about the mating systems of Himalayan water shrews.

Breeding occurs in May, producing a litter of five to seven offspring. Offspring are kept in a small chamber constructed in a riverbank, which usually has several openings, and one of these openings will typically be underwater. (Sterndale, 1884)

  • Breeding season
    May
  • Range number of offspring
    5 to 7

Little is known about the parental investment provided by the Himalayan water shrew. As previously mentioned, there are several offspring per litter, and the young are housed in a chamber in a riverbank. (Sterndale, 1884)

Lifespan/Longevity

Himalayan water shrews have never been kept in the captivity, and little is known about their lifespan, but they are assumed to be short-lived. (Li and Boren, 1999)

Behavior

Little is known about the behavior of the Himalayan water shrew other than it is an semi-aquatic mammal associated with clear, swift-flowing streams and rivers. (Sterndale, 1884; Yuan, et al., 2013)

Home Range

Home range and territory size of individuals is unknown.

Communication and Perception

Little is known about the communication and interactions of Himalayan water shrews. The presence of long whiskers suggests reliance on tactile senses. (Sterndale, 1884)

Food Habits

Due to high metabolic demands, soricines consume as much as three times their body weight in 24 hours and can survive only a few hours without feeding.

Himalayan water shrews are insectivores. Samples of the stomach contents of C. himalayica show consumption of only insects and spiders, such as fishing spiders (Family Pisauridae). There is no evidence they consume crustaceans or fish, a common food source to other species of water shrews. (He, et al., 2010; Lunde and Musser, 2002)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods

Predation

Little is known about predation on this species, and no predators have been identified.

Ecosystem Roles

C. himalayica are thought to be ecological competitors with Nectogale elegans, another water shrew of similar body size, that shares a similar habitat of swift-flowing streams in forested mountainous regions. Both are found in high altitudes (up to 3048 m), with large altitude ranges (>2000 m). These two species have never been documented to coexistence, suggesting direct ecological competition.

Himalayan water shrews are commonly infected with the larvae of Gnathostoma nipponicum. Infection rates in the wild have been documented at >70% of the population. (Jenkins, 2013; Oyamada, et al., 1996)

Commensal/Parasitic Species
  • Gnathostoma nipponicum

Economic Importance for Humans: Positive

C. himalayica is harvested for local medicinal uses. (Molur, 2008)

Economic Importance for Humans: Negative

Although the primary habitat of this species is swift flowing streams and rivers, individuals have occasionally been found in ditches, fields, houses and barns. This presence may lead humans to perceive the Himalayan water shrew as a pest. (Sterndale, 1884)

  • Negative Impacts
  • crop pest
  • household pest

Conservation Status

C. himalayica is classified by the IUCN as a species of least concern which is justified by wide geographic distribution (>2000 km), presumed large population size and the unlikeliness of a rapid population decline. Identified threats to this species include: habitat lost due to agricultural expansion and logging, harvesting for medicinal use, pest control methods, and a decline in prey species. The effects of rain forest logging on the Southeast Asian population of C. himalayica have been investigated, but these studies have been inconclusive, due to the elusiveness of this species. (Jenkins, 2013; Molur, 2008; Wells, et al., 2007)

Contributors

Kirsten Solmundson (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

bilateral symmetry

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

drug

a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease

endothermic

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.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

freshwater

mainly lives in water that is not salty.

insectivore

An animal that eats mainly insects or spiders.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

temperate

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).

terrestrial

Living on the ground.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Francis, C. 2008. A Field Guide to the Mammals of South-East Asia. London, Cape Town, Sydney, Auckland: New Holland Publishers Ltd. Accessed November 30, 2015 at https://books.google.ca/books?id=zWeS8A6nunIC&pg=PA184&lpg=PA184&dq=himalayan+water+shrew&source=bl&ots=ekTFtMlz0z&sig=R2F7zqFG-aIVkhPASS1bfcNsVbs&hl=en&sa=X&ved=0ahUKEwi-ieDsgLnJAhXFGB4KHcdpCf0Q6AEITDAL#v=onepage&q=himalayan%20water%20shrew&f=false.

He, K., Y. Li, M. Brandley, L. Lin, Y. Wang, Y. Zhang, X. Jiang. 2010. A multi-locus phylogeny of Nectogalini shrews and influences of the paleoclimate on specialization and evolution. Molecular Phylogenetics and Evolution, 56/2: 734-746.

Ichikawa, A., H. Nakamura, T. Yoshida. 2005. Mark-recapture analysis of the Japanese water shrew Chimarrogale platycephala in the Fujisawa Stream, a tributary of the Tenryu River, central Japan. Mammal Study, 30: 139-143.

Jenkins, P. 2013. An account of the himalayan mountain soricid community, with the description of a new species of Crocidura (Mammalia: Soriciomorpha: Soricidae). The Raffles Bulletin of Zoology, 29: 161-175.

Jones, G., R. Mumford. 1971. Chimarrogale from Taiwan. Journal of Mammalogy, 52/1: 228-232.

Li, Y., J. Boren. 1999. Population Distribution, Habitat Usage, and Conservational Strategy of Himalayan water shrew (Chimarrgogale himalayica) in Taiwan. Tokay University, Republic of China: Council of Agriculture Forest Service. [Translated].

Lunde, D., G. Musser. 2002. The capture of the Himalayan water shrew (Chimarrogale himalayica) in Vietnam. Mammal Study, 27: 137-140.

Molur, S. 2008. "Chimarrogale himalayica" (On-line). The IUCN Red List of Threatened Species. Accessed November 01, 2015 at http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T40614A10341024.en.

Mōri, T., S. Arai, S. Shiraishi, T. Uchida. 1991. Ultrastructural observations on spermatozoa of the soricidae, with special attention to a subfamily revision of the japanese water shrew Chimarrogale himalayica. Journal of the Mammalogical Society of Japan, 16: 1-12.

Oyamada, T., H. Kobayashi, T. Kindou, N. Kudo, H. Yoshikawa, T. Yoshikawa. 1996. Discovery of mammalian hosts to Gnathostoma nipponicum larvae and the prevalence of the larvae in rodents and insectivores. Journal of Veterinary Medicine Science, 58/9: 839-843.

Sterndale, R. 1884. Natural History of the Mammalia of India and Ceylon. Calcutta: Thacker, Spink. Accessed December 03, 2015 at https://archive.org/details/naturalhistoryof00ster.

Wells, K., E. Kalko, M. Lakim, M. Pfeiffer. 2007. Effects of rain forest logging on species richness and assemblage composition of small mammals in Southeast Asia. Journal of Biogeography, 34: 1087-1099.

Yuan, S., X. Jiang, Z. Li, K. He, M. Harada, T. Oshida, L. Lin. 2013. A mitochondrial phylogeny and biogeographical scenario for asiatic water shrews of the genus Chimarrogale: implications for taxonomy and low-latidue migration routes. PLoS ONE, 8/10: 1-15.

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