(European or fish) otter (Lutra lutra) is a marten -like fish hunter with dark brown waterproof and fast drying top coat to keep the insulation, air -containing inner layer of densely planted fuzz hairs underwater dry.
Males measure 60 to 90 centimeters with a tail of 36 to 47 centimeters and a weight of 6 to 17 kilograms. The shoulder height is approximately 30 centimeters. Females are smaller and lighter.

otterThe long, oval and round strong, tapered tail serves as a stabilizer and rudder while swimming.
The otter has five webbed toes. (A dog track has only four toes.)
The eyes and the small lockable ears and nostrils are aligned so they keep on swimming just above water.

Otters are very shy, solitary and mostly active at night. They live in freshwater areas with plenty of cover, with rivers, lakes, canals, streams and swamps.
The territory of a male otter must include at least 16 kilometers of clean and undisturbed shoreline sides. It is regularly marked by small piles defecation.
He uses several steady resting places and caves, among tree roots, or ancient caves include muskrats or rabbits, beavers. The otter does not hibernate.

The otter always leaves the water at same locations.
On that trampled otter corridor are usually found feces containing fish scales and bones. These 'spraints' are usually 10 to 15 mm thick and 2 to 10 cm long.

They love sloping slippery clay or ice hills playful and frequently as a slide.
He is often on the hind legs, the tail as support, on the lookout.

While foraging, they can take 3 to 10 kilometers and swim in one track 7 to 8 hours, with an average speed of 1.5 to 2 kilometers per hour.
Otters dive ten to forty seconds under water, but can be up to four minutes under. They could at least swim 400 meters underwater at speeds between 11 and 14 kilometers per hour.

The otter eats mainly fish, but also other aquatic animals: amphibians, waterfowl, rats, crayfish, crabs, worms, insects.
An adult otter eats per day about 2 % of its body weight.
In turbid water the otter uses his 17 to 18 mm long whiskers, with which he can feel the movements of fish in the water.
Small fish, he eats mostly in the water. He lies on his back and holding the prey with both front legs. Large prey, he drags first on land to eat them there.

After a gestation period of 61 to 63 days the mother, who cares alone for the offspring, gets in the spring or summer 2 or 3 little ones. In the wild he lives 3 to 4 years, in captivity to 15 years.

Otters were seen as harmful game. The government paid premiums for killed otters in the Netherlands until 1942, in Belgium until 1965. As fish concurrent and for its fur he was hunted.
Fuel oil and detergent remove the coat ‘s waterproof, so the animals can die of cold.
Traffic, fishing nets, habitat disturbance and lack of food took their toll.
Fertilizers and pesticides gave the death blow. They accumulate in aquatic life, fish and eventually accumulate in the otter. So he is considered to be extinct in the Netherlands and Flanders.
Maybe he gets still a small chance by reintroduction and migration (from Wallonia and Germany)?

Previously -trained specimens were used for fishing (nowadays still in China).
Otters are easily tamed and can as a hunting dog capture fish and and bring waterfowl to their boss.

Spring 2012: After 20 years for the first time is spotted an otter in Flanders (Willebroek). Later also in Ranst (Antwerp) and Bocholt (Limburg). In 2014 an otter was filmed in the nature reserve 'Tafelbos' in Lubbeek with a wild camera at the Vossel Beek (Vlaams-Brabant).