Neomys fodiens occurs throughout Eurasia, to western Siberia, northern Asia Minor, the Pacific coast of Siberia, and North Korea.
Biogeographic Regions: palearctic (Native )
A darkly colored shrew with a white underside. Coloration on dorsal and ventral sides are sharply demarcated. A fringe of bristles runs along the ventral surface of the tail and on the paws which are thought to serve as a swimming aid. Teeth have red tips. Females have five pairs of mammae.
Average mass: 15 g.
Average basal metabolic rate: 0.328 W.
Catalog Number: USNM 101311
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Male; Adult
Preparation: Skin; Skull
Collector(s): R. Young
Year Collected: 1899
Locality: Montrejeau, Haute-Garonne Department, Midi-Pyrenees, France, Europe
- Type: Miller, G. S. 1901 Apr 25. Proceedings of the Biological Society of Washington. 14: 45.
Habitat and Ecology
Found on the banks of both standing or flowing fresh water and adjacent areas.
Terrestrial Biomes: forest
Aquatic Biomes: lakes and ponds; rivers and streams
These shrews forage almost exclusively underwater, efficiently preying on aquatic invertebrates such as snails, mollusks, freshwater insects, and also small vertebrates such as fish, amphibians and frogs. Prey are weakened by a poisonous secretion from the submaxillary gland. They generally forage by taking a dive that can last up to 20 seconds. After coming onto land, water shrews quickly run into their burrows and emerge a moment later almost dry, after coming through the tight squeeze of the tunnel where the water is absorbed by the soil. The process is then repeated a few meters away along the stream bank. Water shrews are also known to eat some terrestrial insects as well, such as dipteran larvae.
Life History and Behavior
Status: wild: 3.0 years.
Status: captivity: 1.6 years.
Lifespan, longevity, and ageing
The breeding season in England occurs fom April to September, with multiple litters per season. Litter size can be between 3 and 12, more commonly 5 or 6. Gestation lasts approximately 20 days, and lactation twice that. Sexual maturity is reached between 6 and 8 months.
Average birth mass: 0.78 g.
Average gestation period: 20 days.
Average number of offspring: 5.
Average age at sexual or reproductive maturity (male)
Sex: male: 106 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 106 days.
Molecular Biology and Genetics
Statistics of barcoding coverage: Neomys fodiens
Public Records: 1
Specimens with Barcodes: 10
Species With Barcodes: 1
Barcode data: Neomys fodiens
There is 1 barcode sequence available from BOLD and GenBank. Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen. Other sequences that do not yet meet barcode criteria may also be available.
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IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Lower Risk/least concern(Baillie and Groombridge 1996)
Quite common within its geographical range.
IUCN Red List of Threatened Species: least concern
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
No negative impacts known.
Economic Importance for Humans: Positive
These shrews eat the larvae of insects which some humans find bothersome.
Eurasian water shrew
The Eurasian water shrew, Neomys fodiens, known in the United Kingdom as the water shrew, is a relatively large shrew, up to 10 cm (4 in) long, with a tail up to three-quarters as long again. It has short, dark fur, often with a few white tufts, a white belly, and a few stiff hairs around the feet and tail. It lives close to fresh water, hunting aquatic prey in the water and nearby. Its fur traps bubbles of air in the water which greatly aids its buoyancy, but requires it to anchor itself to remain underwater for more than the briefest of dives.
Like many shrews, the water shrew has venomous saliva, making it one of the few venomous mammals, although it is not able to puncture the skin of large animals such as humans. Highly territorial, it lives a solitary life and is found throughout the northern part of Europe and Asia, from Britain to Korea.
The Eurasian water shrew grows to a length of about 10 cm (4 in) long with a tail length of 8 cm (3 in) and weight of 15 to 19 grams (0.53 to 0.67 oz). The dense short fur on the head, back and sides is greyish-black. The underparts are dirty white and are sharply demarcated from the dorsal surface. Sometimes they are tinged with rusty brown or occasionally are entirely dark grey. There is a white spot just behind the eye and often another near the small, rounded ear which is nearly hidden in the fur. The nose is black and the snout long and tapering. The sharp, mostly white teeth are tipped with red, typical of the shrew subfamily Soricinae. The rusty colour comes from deposits of iron which serve to harden the enamel and which are concentrated in the tips of the teeth, particularly the molars which are the teeth most subject to wear. The female has five pairs of nipples. The legs are short and the hind feet are powerful, with a fringe of short, stiff hairs on the outer edge, both of which features assist while it is driving its body through the water. The tail is slender and has a keel of short white hairs on the underside. This shrew often utters shrill cries as it scurries about.
Distribution and habitat
The Eurasian water shrew is found throughout Europe with the exception of Iceland, Ireland, The Iberian Peninsula, certain Mediterranean islands and the Balkans. In Asia, its range extends from western Siberia ans Asia Minor to North Korea and the Pacific coast of Siberia. It rarely strays far from water and is found in and around ditches, streams, ponds, watercress beds, fish ponds, damp meadows and rough bushy ground adjoining water.
Outside the breeding season, both male and female Eurasian water shrews maintain a territory but during the breeding season, only the females do so. At this time the males wander about visiting various female territories which indicates a promiscuous mating system without pair bonding. On the whole they are solitary animals that seem to mutually avoid each other and there is no social hierarchy.
The breeding season extends from April to September and much of the courtship takes place in the water. It either uses pre-existing burrows or digs its own. The nesting chamber is lined with moss, dry grass and leaves. Litters of four to eight or more young are born after a twenty four day gestation period. The young are tiny and helpless at birth. Their eyes open at fifteen to eighteen days and they are fully weaned at about seven weeks. Females can produce two or three litters a year. The juveniles disperse after weaning, setting up their own territories. They are sexually mature at six to eight months and their life expectancy is about three years.
The Eurasian water shrew is active both night and day and is thoroughly at home in the water. Its short fur holds air and the skin does not get wet when it swims. When it emerges from the water it enters one of its many burrows and any moisture adhering to the fur is absorbed by the earth walls. It mostly feeds on aquatic organisms which are caught while it is swimming. It can remain underwater for twenty seconds before it has to surface to breathe. Larger prey items can be subdued by the toxic secretions from its submaxillary glands. They feed on crayfish, water snails, small fish, aquatic larvae, insects, spiders, amphibians, especially newts and small rodents are also eaten. It also feeds on land on such things as insect larvae.
The Eurasian water shrew has a pair of glands under its jaw which produce venom, and this has been shown to be potent against the field vole (Microtus agrestis), and lethal at a minimum dose of fifteen milligrams per kilogram body weight. The venom consists of a paralytic peptide which has been patented for use in neuromuscular therapy.
The International Union for Conservation of Nature lists the Eurasian water shrew as being of "Least concern" in its Red List of Threatened Species. This is because it has a large population distributed across a wide range and its population seems fairly stable. In some areas habitat degradation is occurring and wetlands are being drained but not to such an extent as to increase the status to "Vulnerable". Other possible threats include agricultural products and sewage which may pollute waterways and reduce the availability of food. In western Spain, a separate subspecies (N. f. niethammeri) has a very limited range and may be declining in numbers.
- Hutterer, R. (2005). "Order Soricomorpha". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. p. 279. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Hutterer, R., Meinig, H., Bertolino, S., Kryštufek, B., Amori, A., Sheftel, B., Stubbe, M., Samiya, R., Ariunbold, J., Buuveibaatar, V., Dorjderem, S., Monkhzul, Ts., Otgonbaatar, M. & Tsogbadrakh, M. (2008). "Neomys fodiens". IUCN Red List of Threatened Species. Version 2013.1. International Union for Conservation of Nature. Retrieved 2013-09-14.
- Konig, Claus (1973). Mammals. Collins & Co. pp. 23–26. ISBN 978-0-00-212080-7.
- Strait, S. G.; Smith, S. C. (2006). "Elemental analysis of soricine enamel: pigmentation variation and distribution in molars of Blarina brevicauda". Journal of Mammalogy 87 (4): 700–705. doi:10.1644/05-MAMM-A-265R4.1.
- Fahey, Bridget (1999). "Neomys fodiens: Eurasian water shrew". Animal Diversity Web. University of Michigan Museum of Zoology. Retrieved 30 August 2013.
- Cantoni, Debora (1993). "Social and spatial organization of free-ranging shrews, Sorex coronatus and Neomys fodiens (Insectivora, Mammalia)". Animal Behaviour 45 (5): 975–995. doi:10.1006/anbe.1993.1116.
- Dufton, Mark J. (1992). "Venomous mammals". Pharmacology & Therapeutics 53 (2): 199–215. doi:10.1016/0163-7258(92)90009-O.
- "Patent: Paralytic peptide for use in neuromuscular therapy". Patent 7485622. United States Patent Office. 3 February 2009. Retrieved 30 August 2013.