Living Organisms / Animalia / Craniata / Mammalia / Carnivora / Mustelidae / Lutra / Species
Lutra lutra - European otter (Click photographs/illustrations: full picture & further details)
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General and References

Alternative Names (Synonyms)

  • Otter
  • Eurasian river otter
  • European river otter
  • Loutre commune (French)
  • Loutre d'Europe (French)
  • Eurasiatischer Fischotter (German)
  • Fischotter (German)

Alternative species names (the second part of the binomial species names): [Genus] amurensis; [Genus] angustifrons; [Genus] aureventer; [Genus] aurobrunneus; [Genus] baicalensis; [Genus] barang; [Genus] ceylonica; [Genus] chinensis; [Genus] fluviatilis; [Genus] hanensis; [Genus] indica; [Genus] intermedia; [Genus] japonica; [Genus] kamtschatica; [Genus] kutab; [Genus] marinus; [Genus] meridonalis; [Genus] monticolus; [Genus] nair; [Genus] nepalensis; [Genus] nippon; [Genus] nudipes; [Genus] oxiana; [Genus] piscatoria; [Genus] roensis; [Genus] seistanica; [Genus] sinensis; [Genus] splendida; [Genus] stejnegeri; [Genus] vulgaris; [Genus] whiteleyi (B141).

Names for new-borns / juveniles

Names for males Dog
Names for females Bitch

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General Appearance

Elongated body, short legs, flat head, short neck similar width to skull, small eyes and ears, broad muzzle, prominent whiskers, long tail with broad base, flattened and smoothly tapering (B142, B144, B147, B148).

Similar Species

Sexual Dimorphism --

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Species Author

Debra Bourne

Major References

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

Husbandry references:

(UK Contacts)

(Further Reading)
Click image for full contents list of ELECTRONIC LIBRARY

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

Parent Group

  • Land carnivores: Mustelidae

Specific Needs Group referenced in Management Techniques

  • Land carnivores: Mustelidae

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Husbandry Information


Individual Techniques linked in Wildpro

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Appearance / Morphology

Measurement & Weight

Length Head-body length:  22-38in./55-95cm (B144), up to 100cm B148.
Height At shoulder: about 30cm B148.
Adult weight General 11-26 lbs./5-12kg (B144); up to 12 kg (B148).
Male --
Female --
New-born weight 3.5-4.3oz./100-120g (second day) (B144).
Growth rate --

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  • Broad, flat and rounded.
  • Skull: Narrow post-orbital constriction (B142).
  • Nose: Nostrils high on head, can be closed under water. Long whiskers (vibrissae) on upper lip and mouth corners.
  • Ears: small, round, nearly hidden in fur, can be closed under water.

(B52, B144, B147, B148)

Dentition (Teeth) I 3/3 C 1/1 P 4/3 M 1/2 x2 =36 (B148).
Eyes High on head (B148).

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Legs and Tracks

  • Short powerful legs.
  • Five toes.
  • Webbed toes.
  • Strong claws

(B52, B142, B144, B147, B148)

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  • Thick base, muscular, rounded, underside flattened, tapering.
  • Used as rudder when swimming.

(B52, B144, B147, B148)

Length: 35-40cm (B52); 12-22in./30-55cm (B144), up to 50 cm B148.

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Coat / Pelage

Adult Female
  • Dorsal: glossy dark brown or chestnut brown
  • Ventral: ventral slightly lighter brown.
  • Throat: pale - buff to cream.
  • Chin: may have white patch.
  • Fur thick, dense: fine thick wool, upper hair, coarse shiny bristles.
  • Dense underfur - remains dry when in water.
  • Coat appears shiny when wet and spiky after shaking.

(B52, B142, B144, B148)

Variations (If present) Asian races:
  • Coat may be paler brown (B52).
Moult Once a year, extended (B142).
New-born / Juvenile --

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Neonate (New-born) Characteristics

12cm long, furred, blind (B142).

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

  • Reproductive: two or three pairs of nipples (B142, B144).
  • Scent glands: anal gland either side of anus, proctodeal glands discharging into rectum (B142).

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Life Stages / Natural Diet / Physiology

Reproductive Stages

Breeding Season
  • Non-seasonal (B52).
  • Probably non-seasonal over most of Britain. Shetland births mainly May to August (B142).
Oestrus / Ovulation --
Gestation / Pregnancy
  • 61-63 days, but prolonged over 9 months (B144).
  • 62-63 days, no delayed implantation (B142).
  • 61-65 days (B52).
Parturition / Birth --
Neonatal development
  • Birth: blind.
  • 2-3 weeks: start crawling.
  • 4-5 weeks: eyes open.
  • 7 weeks: first solid food eaten, increasing activity levels.
  • 8 weeks: permanent molars erupt.
  • 12 weeks: swimming.


  • Fishing with mother by 8 weeks (B148).
  • Dispersal probably 8-12 months old (B142).
Litter size 2-4, rarely 5 (B144) 9-10 (B148); 1-5 , usually 2-3 (B142); 2-5 usually 2-3 (B52).
Time between Litters / Litters per year --
Lactation / Milk Production 3-4 months (B144) 14 weeks (B142).
Sexual Maturity In second or third year (B144); 17 months male, 22 months female (B142).
Longevity Up to 22 years in captivity (B144).

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Natural Diet

  • Fish, frogs, crayfish, crabs, other aquatic invertebrates.
  • Also birds (waterfowl, waders, passerines), rarely mammals (rabbits, water voles).
  • Sometimes aquatic insects.
  • Mainly fish in most areas, some places more frogs or crayfish, and in coastal areas crabs may be up to 20% of diet.

(B142, B144, B147, B148)

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

Temperature --
Pulse --
Respiration --
  • (Spraints). Deposited often on prominent features e.g. logs and rocks, and same places used regularly.
  • Dark, mucilaginous, musky smell when fresh. Reach 10cm long/1cm diameter.


Haematology / Biochemistry --
Chromosomes --
Other --

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Feeding Behaviour

  • Hunt for fish catching with mouth.
  • Dive for crustaceans and clams.

(B144, B147)

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Parental Behaviour


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Social Behaviour / Territoriality

  • Mainly solitary (B142).
  • Territory shoreline strips 320ft/100m wide, 1- more than 30 miles long /2-50km long (B144). 1 animal per 2-3km lakeshore or 5km of stream - 0.7-1.0 animal per square km of water (B147). Straight line home range 15km males, 7km females (B147).
  • Home ranges may be small (few hundred metres) in very productive areas (B142).
  • Examples include: Shetland 2-13km of coast, Perthshire male 39km river, females 16 and 22 km of river. Sweden females 4-8km across on lakes and interconnecting streams, with 11-21km for males (B142).
  • Male territories exclusive of other males, female territories exclusive of other females (B147).
  • Variable overlap female territories with one another (overlap in Perthshire, but exclusive in Sweden) (B142).
  • Variable overlap male territories (Partial overlap Sweden, in Perthshire less overlap than for females) (B142).
  • Male range territories may overlap with several females (B147).
  • Territories marked with scent (B147). Mark home ranges with spraints, particularly males (B142).
  • Occasional fights (B147). Fights not recorded in wild (B142).
  • Dominance hierarchy among males, with favoured territory to highest ranking animal (B142, B147).
  • Males mainly solitary (B147) but may join female when cubs about 6 weeks old (B147).
Inter-specific --

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Sexual Behaviour

  • Vigorous chasing and play involved in courtship, with pair staying together for about one week.
  • Mate on land or in water.


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Predation in Wild

  • Skuas may take very small juveniles in Shetland.
  • On continental Europe, sea eagles, wolves, lynx.


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Activity Patterns

  • Use fixed runs within territory.
  • Walk, run and bound on land.
  • Expert swimmer and diver, closing nostrils and ears when under water and surfacing every few minutes to breath.
  • Swim using all four legs at surface, and by lumbar dorso-ventral flexion under water.
  • Usually rest in holt or dense cover above ground.
  • Rest in open usually for short times, including sunning.
  • Playful.

(B142, B144, B147, B148)

  • Active dusk and night, but also in daytime if not disturbed (B144).
  • Hunt at night (B148).
  • Mainly nocturnal on rivers but active in day on coasts, particularly early morning/late evening in summer (B142).

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Habitat and Range

General Habitat Type

  • Lakes, rivers, streams, marshes, also coasts.
  • Travel overground between watersheds.

(B142, B144)

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Nests / Burrows / Shelters

  • Holt may be dug, or natural hole used, in bank of river/stream/lake.
  • Entrances below water level.
  • Dens may have several passages.
  • Living chamber/nest above water level, with dry leaves and grass lining.
  • With ventilation shaft.

(B147, B148)

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Distribution and Movement (Migration etc.)

Normal Palearctic and Oriental regions: Eurasia south of tundra line, North Africa, Sri Lanka, Taiwan, Sumatra, Java: found from Scotland to Kamchatka and south to Java.
  • Not found: Mediterranean islands (except Corfu, Lesbos, Chios, Euboea). Probably extinct in Lichtenstein, Netherlands, Switzerland. (B143).
  • Europe: Good populations remaining: Portugal, Ireland, Greece, Scotland, northern taiga of Russia Natural recovery: Finland, Great Britain (B143).
  • Britain: Remain through Ireland and most of Scotland. Reasonable populations south-west England and counties bordering mid-Wales, with low populations in north, south and eastern England, while absent from south Wales, Anglesey, central England (B142).

(B51, B52, B143, B147, B148)

Occasional and Accidental --

Reintroduction/restocking projects Switzerland, Sweden, Great Britain, Spain (B142, B143).

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Intraspecific variation

  • Ten subspecies recognised. Small differences between subspecies and not well investigated (B143).
  • No subspecies recognised (B142).

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Conservation Status

Wild Population -
  • Formerly widespread in Europe, but declined central and northern Europe, to extinction in some areas. (B143, B144, B148).

  • Crashes in populations 1960s-1970s, (B143); severe declines from 1957 thought due to organochloride pesticides, also PCBs, heavy metals (B142).

  • In Britain: native, population localised but generally increasing. Pre-breeding population estimate for mid-1980's of about 7350, with 350 in England, 6600 in Scotland, 400 in Wales. Significantly higher population by mid 1990s. Population estimate of this widely-distributed species was based on a limited amount of data and considered likely to be inaccurate by up to 50% in either direction (B221).

General Legislation
  • Bern Convention Appendix II (B143).
  • EU Habitats & Species Directive, Annex II & Annex IV (B143).
  • EC 338/97 Annex A (B143).
  • Protected under Wildlife and Countryside Act 1981 in Britain, also protected in Northern Island (B142).
  • This species is 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)
CITES listing
  • Appendix I (Reservation by Russian Federation) (B143).
  • Appendix I (B147).
Red-data book listing Vulnerable (B51).
  • Formerly chemical pollution, hunting (for fur and sport), habitat loss. Now widely protected against hunting (B142, B143).
  • Also road traffic accidents, incidental capture in fish/crustacean traps (B142, B143, B221).
  • Possible role of decreased river/lake productivity due to acidification (B143, B221).
  • PCB contamination may influence population recovery (B143, B221).
  • Potential threat to coastal populations from oil spills (B221).
Captive Populations
  • EEP (European Breeding Programme) started 1985 for self-sustaining captive population, with total captive population about 200 animals.
  • As of 1993, 55 of 60 holders of otters had agreed to co-operate in EEP and their animals were included in the studbook.


Trade --

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