Alternative Names (Synonyms)

• Water shrew
• Northern water shrew
• European water shrew
• Otter shrew
• Water ranny
• Labhallan (Scottish Gaelic)
• Sorex fodiens
• Sorex aquaticus
• Sorex bicolor
• Amphisorex pennanti
• Crossopus sowerbyi

Names for new-borns / juveniles

General Appearance

Similar Species

• Black dorsal surface
• Prominent keel of stiff hairs on underside of tail
• Teeth: red-tipped teeth, four pairs of upper unicuspid teeth, smooth unlobed first lower incisors.

(B142).

References

Species Author

Major References

• B51, B52, B141, B142, B143, B144, B147, B148, B221
• D30

Husbandry references:
J23.15.w1, J23.26.w1, B142, B22.27.w4, B156.12.w12

• Wildlife and Countryside Directorate, Department of the Environment, Transport and the Regions (DETR)
• The Mammal Society
• Mammals Trust

• British Mammal Factsheets

TAXA Group (where information has been collated for an entire group on a modular basis)

Parent Group

Specific Needs Group referenced in Management Techniques

Husbandry Information

Notes

• Shrews are easy to trap, and will die from cold, starvation and stress if not found rapidly Traps intended for shrews should be visited every two hours; traps intended for other small mammals should contain food suitable for shrews (B142).

• Accommodation of Casualty Shrews
• Hand-rearing Shrews
• Catching and Handling of Shrews
• Feeding of Casualty Shrews
• Release of Casualty Shrews

Measurement & Weight

• Head-body length:2.5-3.8in/62-95mm (B144); 67-96mm (B142); up to 8cm (B148).

• 12-19 g, pregnant females up to 28g (B142).
• 0.4-0.7oz./10-22g (B144).

• 10-15g (B156.12.w12).

• 10-15g (B156.12.w12).

• 0.03oz/1g (B144).

Head

Nose: Snout narrow and pointed (D30).

Ears: Small (D30)

• I 3/2, C 1/0, P 2/1, M 3/3.
• Red-brown tooth tips.
• Permanent dentition at birth.

(B52, B142, B148)

Legs and Tracks

• Legs short (D30). Fore and hind feet fringes stiff white hairs - probably aid in swimming (B52, B142).
• Hindfoot length: 15-16mm (B142).

Tail

• Slender. Underside of tail has prominent keel of elongated stiff hairs (B52, B147, B148, D30).
• Length:1.8-2.9in/46-74mm (B144) ; 45-77mm (B142).

Coat / Pelage

• Dorsal: black or very dark brown.
• Sharp demarcation line dorsal/ventral.
• Ventral: silvery-grey or white with variable midline yellow or brown wash.
• Tail: dorsal dark brown, ventral white.
• Fore and hind feet: fringes of stiff white hairs - probably aid in swimming.

(B142, B148).

• Melanism common - ventral surface dark.
• Albinos rare.
• Some distinctive insular populations, e.g. Shuna (Strathclyde) animals small with ventral uniform pale grey.

(B142).

• Autumn moult: probably tail to head.
• Spring moult: probably head to tail.
• Summer moult: occasionally; head to tail.

(B142)

Neonate (New-born) Characteristics

Detailed Anatomy Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

• Reproductive: Five inguinal pairs of nipples (versus three pairs in Sorex spp.) (B142, B147).
• Scent glands: on thoracic area of flanks (further forward than in Sorex spp.) highly developed only in adult males, and fringed with white hairs (B142).

Natural Diet

• Wide variety invertebrates.
• Freshwater crustaceans Gammarus, Asellus and cased caddis fly larvae are dominant prey in Britain.
• Also terrestrial beetles, spiders, centipedes, molluscs, crabs, earthworms.
• Also small fish, frogs, newts, birds

(B142, B144, B147, B148).

Detailed Physiology Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

Feeding Behaviour

• Forage both on land and underwater, eating about. 50% of body weight/day.
• Bring aquatic prey onto land to eat, sometimes caching killed and partially eaten prey.
• Take prey larger than they are themselves, with some evidence of assistance from a venom in saliva (produced by submaxillary glands) - if injected into mice affects nervous, respiratory and blood systems, while bite in humans results in burning pain and skin reddening persisting for a few days.

(B142, B147)

Parental Behaviour

Social Behaviour / Territoriality

• Essentially solitary, but live close to neighbours.
• Aggressive, but less intraspecific aggression than common or pygmy shrew, more tolerant of one another.
• Intermittent nomadic existence - shift home range every few months.
• Home range about.20-30 square m on land, 60-80 square metres including water surface.
• Home ranges overlap at peripheries.
• Densities vary greatly with location and season.
• Appearance of stranger leads to squeaking and "churr-churr" sound, sometimes chases and scuffles (resident usually victor), but will settle and coexist especially if can establish separate nests.
• Males wander across ranges of several females in breeding season.

(B52, B142, B147)

Sexual Behaviour

Predation in Wild

• Owls, fish (B144).
• Carnivorous mammals, birds (including tawny owl, barn owl), fish (B142).

Activity Patterns

• Move quickly
• On ground surface less in winter than in spring, summer.
• Mainly use small stretch of bank and adjacent water, with daily movement about 10-60m, rarely 150-200m, and less in winter than in summer.
• Good swimmer and diver.
• Swim by 'dog-paddle, all four limbs, dive frequently (propulsion from hind legs), up to 75cm or more in still water.
• Buoyancy provided by air trapped in dense coat may limit time spent submerged - often anchor against rocks and plant stems to remain under water.
• May be submerged 5-20 seconds.
• Groom mostly after swimming, removing water from fur by shaking, scratching with hind feet and squeezing through burrows.

(B142, B147, B148).

• Active day and night but mostly during darkness.
• Peak activity just before dawn and minimal in late morning.

(B52, B142)

General Habitat Type

• Banks of unpolluted standing and flowing water such as rivers, streams and ponds, and adjacent areas, also swamps, marshes, humid woodland, wet meadows.
• In northern parts of range (occasionally in Britain) away from water e.g. fields, gardens.
• In southern part of range found in mountainous areas, up to 2500m in Alps, along fast-flowing mountain streams, small rivers, riverine forests, lake reedbeds.

(B51, B143, B144, B148, D30)

Nests / Burrows / Shelters

• Make and use extensive burrow systems in stream banks, usually with entrance above water.
• May modify & take over burrows of other small mammals.
• Nest below ground in burrows, with rounded sleeping nests of moss, dried leaves and grass, small stones - one or two entrances.

(B52, B142, B148)

Distribution and Movement (Migration etc.)

• World: Palearctic - Britain and Arctic Scandinavia across Europe and western Siberia to Lake Baikal, Far East (northen Asia Minor, Pacific coast of Siberia, North Korea), and Sakhalin Island.
• In Europe: south to Cantabrian mountains, Pyreneess, Alps, Abruzze, Balkan Peninsula mountains.

(B51, B143, B147).

--.

Intraspecific variation

• Neomys fodiens niethammeri (Bühler, 1963) generally recognised as a valid subspecies, from northern Spain.
• Neomys fodiens bicolor British water shrew (Shaw, 1791) not usually recognised as a subspecies.

(B143)

Conservation Status

• Common (B143).

• In Britain: native, locally common. Pre-breeding population estimate of about 1,900,000, including 1,200,000 in England, 400,000 in Scotland, 300,000 in Wales. Population estimate was "based on a very limited amount of information for the species" although additional knowledge "may not necessarily have made a substantial difference to the estimate". (B221)

• Berne Convention, Appendix III (B143).
• All shrews are listed on Schedule 6 (Animals which may not be killed or taken by certain methods) of the LUK2 - Wildlife and Countryside Act 1981 of the United Kingdom. (W5.Oct01)

• Local habitat loss due to wetland drainage, river bank destruction.
• Also food shortages as water acidified or polluted with pesticides and fertilisers.

(B143, B221).