Chimarrogale himalayica

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.

• Biogeographic Regions
• palearctic palearctic
  • native native
• oriental oriental
  • native native

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.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• forest forest
• mountains mountains

• Aquatic Biomes
• rivers and streams

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).

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.

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.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

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.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

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.

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.

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.

• Key Behaviors
• natatorial natatorial
• motile motile

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.

• Communication Channels
• tactile tactile

• Perception Channels
• tactile tactile
• chemical chemical

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.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods

• 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.

Economic Importance for Humans: Positive

C. himalayica is harvested for local medicinal uses.

• Positive Impacts
• source of medicine or drug source of medicine or drug

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.

• 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.

Additional Links

Encyclopedia of Life

Contributors

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

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.