What kind of animal is the Eurasian otter? We will explain its characteristics, ecology, and habitat. As its name suggests, this otter is distributed quite widely from Africa to Asia and Europe. However, it is an endangered species.
What is a Eurasian otter? Basic stats
The Eurasian otter is a carnivorous mammal in the order Carnivora, family Mustelidae, genus Lutra. Its scientific name is Lutra lutra, and its English name is Eurasian river otter or Eurasian otter. Its body length is 58-80cm, its weight is 5-12kg, and its tail length is 30-50cm. The list of information is as follows.
| Japanese（和名） | ユーラシアカワウソ（ヨーロッパカワウソ） |
| English（英名） | Eurasian river otter Eurasian otter |
| scientific name(学名) | Lutra lutra |
| classification（分類） | Mammalia、Carnivora、 Mustelidae、Lutra 哺乳綱、食肉目、イタチ科、カワウソ属 |
| IUCN Status(保全状況) | NEAR THREATENED |
| Length（体長） | 58～80cm |
| Weight（体重） | ５～12kg |
Habitat
The Eurasian otter (Ursus ursus) is widely distributed across the Eurasian continent, including Algeria, Indonesia (Sumatra), Sri Lanka, Tunisia, and Morocco.
- Geographic Distribution
Wide Distribution: Europe, Russia, Central Asia, East Asia (China, Japan)
Range: Almost the entire Eurasian continent except Iceland
Distribution in Japan: Inhabits rivers and lakes in Honshu, Shikoku, and Kyushu (not found in Hokkaido)
- Habitat
Eurasian otters are mammals adapted to aquatic life and prefer the following environments:
Freshwater
Rivers, lakes, wetlands, ponds, canals, etc.
Places with calm water depths and currents rich in fish and crustaceans
Coastal
Sometimes also found on coasts and brackish waters
Prefers areas with abundant food resources and little human activity
Land Use
Rests and nests in aquatic bushes, riverside caves, fallen trees, and rock shelters
Moves to land during breeding and resting seasons
- Habitat Characteristics
Rich Food Resources: Fish, crabs, frogs, small mammals, etc.
Availability of Hiding Places: They require nesting holes and thickets.
Sensitivity to human activity: Difficulty surviving in urban areas and heavily trafficked rivers.
- Habitat Threats
Habitat loss due to river development and bank protection construction.
Decrease in food resources due to water pollution (pesticides and heavy metals).
Poaching and traffic accidents.
What are its characteristics? What kind of creature is it?
The Eurasian otter (European otter) has a black-brown or gray-brown back, and a pale yellow or gray-white back from the throat to the cheeks, chest, and abdomen. Otters live near water and have webbed feet between the fingers of their limbs, so they can swim. They usually live in rivers, lakes, marshes, and coasts. They are nocturnal, but can also be active in the early morning.
- Physical Appearance
Body Length: Approximately 57-95 cm (head and body length), Tail Length: Approximately 35-45 cm
Weight: Approximately 7-12 kg (varies by region and sex)
Body Type: Slender, flexible body with short legs and a flat tail
Coat:
Dark brown on the surface, slightly lighter underside
Highly waterproof, with thick fur to retain body heat
Face: Rounded head, short ears, large, round eyes
Limbs: Well-webbed feet, adapted for swimming underwater
- Athletic Ability
Swimming Ability: Excellent swimming ability, with a maximum dive time of approximately 2 minutes
Land: Capable of quick walking and running
Athletics Ability: Flexible body allows for movement through narrow caves and between rocks
- Diet
Carnivorous: Mainly feeds on fish
Other Food: Crabs, frogs, shellfish, and occasionally small mammals and waterfowl
Prey Method: They chase fish while swimming and catch them underwater.
- Personality and Behavior
Primarily nocturnal or crepuscular (active at dawn and dusk)
Territoriality: Independent populations establish territories.
Sociality: They may live in small family groups.
Warning: Sensitive to predators and humans.
What is their personality like?
Eurasian otters (European otters) are very cooperative, as they sometimes go out to sea and sometimes hunt with their companions.
- Highly Alert
Sensitive to predators and humans, they will immediately retreat into the water if they sense danger.
Sensitive to environmental changes, they have difficulty surviving in areas with development or noise.
- Territoriality
Independent populations form territories.
They mark their territories with urine and feces.
Although multiple individuals may use the same water area, they are generally solitary.
- Sociality
They may form small family groups (mother and child or siblings).
As young animals, they learn hunting and swimming skills by playing with their mother and siblings.
- Activity
Generally nocturnal or crepuscular (active at dawn and dusk).
Curious and actively exploring food and the environment.
- Personality Summary
Highly alert and cautious.
Territorial and independent.
Curious and learns through play and exploration.
Young animals are playful and learn social skills.
💡 Key Points:
Eurasian otters are cautious and wary, yet curious, semi-aquatic predators.
They live in small groups with mothers and offspring, learning skills through play and imitation, and as adults, they live alone, defending their own territories.
What is their ecology like?
Eurasian otters (European otters) mainly eat crustaceans and fish, but they also eat frogs, birds, and small mammals such as rabbits. They breed in the water, have a gestation period of about two months, and can give birth to 1-3 pups at a time. The nursing period is two months and the lifespan is 10 years.
- Life Rhythm
Nocturnal/Crepuscular
Active and forage at night, dawn, and dusk
Daytime: Resting in waterside bushes or burrows
Burrows: Uses safe places such as riverside caves, under fallen trees, and crevices between stones
- Diet
Main Food: Fish (carp, catfish, minnows, etc.)
Side Food: Crabs, frogs, shellfish, and eggs of small mammals and waterfowl
Preying Method:
Pursues prey while swimming and catches them by diving
Can also grab prey with their hands
- Breeding and Rearing
Breeding Season: Mainly spring to summer
Gestation Period: Approximately 2 months
Birth: One calf at a time
Rearing: Mother nurses and protects, and calves become independent at approximately 6 months
Cubs: Practice swimming with their mother to acquire foraging and swimming skills
- Behavior and Movement
Swimming and Diving: They are excellent swimmers thanks to their webbed feet.
Diving time is approximately 2 minutes.
Territorial activity: They can move quickly on riverbanks and on land.
Territory: Each individual has its own territory in each body of water, which they mark by marking.
- Social ecology
They are primarily solitary creatures.
Juveniles and mothers and calves form small groups.
They do not form colonies, and individual habitats may overlap.
- Role in the ecosystem
Aquatic predators: They regulate the populations of fish and crustaceans.
Ecosystem indicator species: They can only survive in environments with good water quality and abundant fish, making them an indicator of the health of the aquatic environment.
Do they have any natural predators?
Natural predators of the Eurasian otter (European otter) include crocodiles and jaguars.
About Eurasian otter cubs
- Life Rhythm
Nocturnal/Crepuscular
Active and forage at night, dawn, and dusk
Daytime: Resting in waterside bushes or burrows
Burrows: Uses safe places such as riverside caves, under fallen trees, and crevices between stones
- Diet
Main Food: Fish (carp, catfish, minnows, etc.)
Side Food: Crabs, frogs, shellfish, and eggs of small mammals and waterfowl
Preying Method:
Pursues prey while swimming and catches them by diving
Can also grab prey with their hands
- Breeding and Rearing
Breeding Season: Mainly spring to summer
Gestation Period: Approximately 2 months
Birth: One calf at a time
Rearing: Mother nurses and protects, and calves become independent at approximately 6 months
Cubs: Practice swimming with their mother to acquire foraging and swimming skills
- Behavior and Movement
Swimming and Diving: They are excellent swimmers thanks to their webbed feet.
Diving time is approximately 2 minutes.
Territorial activity: They can move quickly on riverbanks and on land.
Territory: Each individual has its own territory in each body of water, which they mark by marking.
- Social ecology
They are primarily solitary creatures.
Juveniles and mothers and calves form small groups.
They do not form colonies, and individual habitats may overlap.
- Role in the ecosystem
Aquatic predators: They regulate the populations of fish and crustaceans.
Ecosystem indicator species: They can only survive in environments with good water quality and abundant fish, making them an indicator of the health of the aquatic environment.
Is the Eurasian otter an endangered species?
Unfortunately, the Eurasian otter is designated as an endangered species (red list). Furthermore, international trade is severely restricted by the Washington Convention. Hunting for fur, destruction of habitat and resulting reduction in prey, bycatch, and overhunting as pets are progressing, and the situation is quite critical. In Japan, it was designated as a national natural monument in 1964 and a special natural monument in 1965. Research is also progressing. There is a possibility that it will become extinct like the Japanese river otter.
- International Assessment (IUCN)
Classification: Near Threatened
While there is no imminent risk of extinction globally, there are concerns about population declines and habitat fragility.
Reason:
Population decline due to changes in habitat and water quality
The effects of past overhunting and poaching still persist in some regions.
- Regional Situation
Europe:
In some regions, the species was on the brink of extinction, but is recovering thanks to reintroductions and protection efforts.
Recovering in Western Europe (UK, France, etc.).
Eastern Europe to Russia:
Populations remain relatively stable in some regions.
Japan:
Found sporadically in rivers and lakes in Honshu, Shikoku, and Kyushu.
Local declines due to habitat loss and human activity.
- Causes of decline
Habitat destruction and development
River improvements and bank protection construction have reduced burrows and hiding places
Water pollution
Fish population declines due to pesticides, heavy metals, and industrial wastewater
Poaching and traffic accidents
Populations have declined significantly due to past overfishing
Increasing traffic accidents on riverside roads
Can Eurasian otters be kept as pets?
Since the Eurasian otter is designated as an endangered species, it is quite difficult for ordinary people to keep it as a pet. You can see it at zoos and aquariums. There are also event information and exhibitions, so check it out at shops. Visit the website and check the map.
- Nature of Wildlife
Semi-aquatic predator: Excellent swimmer and diver, living mainly near water.
High physical activity: Travels several kilometers of rivers and lakes daily.
Highly alert and territorial: Independent and sensitive to predators and humans.
Social: Pups and mothers form small groups, but adults are generally solitary.
→ Safely keeping them at home is practically impossible.
- Breeding Laws and Regulations
The Eurasian otter is a Near Threatened species.
Protected under the Wildlife Protection Act and Nature Conservation Act in many countries.
In Japan and Europe, breeding, import, and sale are prohibited without permission.
International trade is restricted by CITES Appendix II.
- Breeding Requirements (for specialized facilities)
Water: Large bodies of water, such as rivers and ponds, where they can swim and dive.
Terrestrial environment: Burrows, bushes, and areas with sheltering rocks for resting.
Diet: They need to be fed a sufficient amount of fish and shellfish daily.
Exercise Management: They need enough space to feed and swim.
Professional Staff: Veterinarians and keepers are needed to manage their health, breeding, and prevent accidents.
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