Eurasian Otter
Lutra lutra
The Eurasian otter is a semi-aquatic carnivore native to Eurasia, characterized by its streamlined body and dense, water-repellent fur. It possesses webbed feet and a muscular tail that facilitate agile swimming and diving in various freshwater and coastal environments. As a top predator, it plays a crucial role in maintaining the balance of aquatic ecosystems. Its presence is often used as a benchmark for high water quality and habitat connectivity.
Details
Identification
Brown fur with a pale throat, flattened head, small ears, powerful muscular tail, five toes with webbing.
Social behavior
Predominantly solitary and territorial; territories are marked with scent-markings (spraints).
Diet
Primarily fish, supplemented by amphibians, crustaceans, small mammals, and waterfowl.
Hunting strategy
Active underwater pursuit using vibrissae to detect prey movements and vibrations.
Overwintering
Active year-round; uses ice-free water patches for hunting and does not hibernate.
Ecology
Ecological role
Apex predator; regulates prey populations and promotes the health of fish stocks by removing weak individuals.
Natural predators
Wolves, lynxes, and large birds of prey (the latter primarily for cubs).
Competitor species
American mink, cormorant, grey heron.
Ecosystem service
Regulation of fish populations and invasive mink; serves as a flagship species for conservation.
Threats
Road traffic, destruction of riparian structures, water pollution (PCBs), and drowning in fishing gear.
Scientific profile
Profile
Distinguishing features
Streamlined body with a flat head and small, closable ears and nostrils. Powerful, muscular tail (rudder) that is thick at the base and tapers. Distinct webbing between all five toes. Long whiskers (vibrissae) on the snout.
Habitat
Demanding regarding water structure; inhabits near-natural rivers, lakes, ponds, and marshes with dense riparian vegetation. Also found in coastal areas, but requires access to freshwater for fur cleaning.
Diet
Opportunistic carnivore focusing on fish (approx. 70-90%). Additionally preys on amphibians, crustaceans (crayfish), waterfowl, and small mammals.
Protection & threats
Main threats
Road traffic (most common unnatural cause of death), habitat loss due to river engineering, bioaccumulation of pollutants (PCBs, mercury), drowning in fishing gear, and illegal persecution.
Population trend
After a massive decline in the 20th century, the trend in Central Europe currently shows a significant recovery and re-expansion.
Conservation measures
Installation of otter ledges under bridges, restoration of watercourses, protection of riparian buffer zones, and use of otter guards in fishing traps.