Range: there are 13 otter species worldwide. The best known are the Eurasian otter, the sea otter and the giant otter of the Amazon. The Eurasian otter, which also lives in Romania, once was widespread on three continents: Europe, Asia and Africa, from the British Islands to Japan and from the North Pole all the way to Northern Africa. They are not present on the islands of the Mediterranean except Corfu, Lesbos, Chios and Euboea. They can be found from sub sea level regions (Holland) to heights of 4000 m (Tibet). Today, due to human persecution and to the diminishing of suitable habitats, the number of the European otter has decreased considerably. In the 1970s and 80s they were on the verge of extinction in France, Belgium and Germany. They are likely to have died out in Liechtenstein and Switzerland. In Holland they became extinct in 1988, but they have been reintroduced later. The most diminished populations live in Central Europe, in great part as a result of improper water management policies. There still are strong populations in Portugal, Ireland, Scotland, the Balkans and in the tundra of Northern Russia. The otter populations of Finland and Britain have grown in the last years.
Biological features: the otter is a member of the mustelids (Mustelidae). In Romania, it is the largest representative of this family, after the badger. Its body constitution is a compromise of adaptation to life in water and on land. The otter is the most adapted predatory mammal to life in water and it is the top predator of water habitats.
Otter fur is thick and consists of two layers: a short and soft layer that serves heat insulation and a long, strong cover fur. The fur is greasy, waterproof and so thick that the air gets trapped between the hairs – this is especially visible when the animals submerge in water. Their colour ranges from light to dark brown, being lighter on the under parts.
Similar to other weasels, the otters’ body is elongated, and has a spindle-like shape with short limbs. Body length is 70-80 cm (28-32 inches) with the tail being 30-40 cm (12-16 inches). As in the case of all other weasels, males are bigger than females: the weight of males varies around 10 kg (22 pounds) and females are 1/3 lighter. Occasionally there are individuals weighing more than 20 kg (45 pounds).
The head of otters is flat and wide. Their ears are small and rounded. While submerged, they can close their nostrils and ears. Around the mouth and nose they have long whiskers which help them find their pray even in muddy waters. Their eyes are placed on the top part of the head. When swimming, only the eyes, ears and nose can be seen. Their teeth indicate a predatory lifestyle. They have sharp canines and molars with which they can seize slithery prey and can crack the lids of cockleshells.
They have 5 webbed toes. They can skillfully hold their prey with the forelegs while eating, while the longer, stronger hind legs are very useful in swimming. When swimming calmly, they row with all four legs like dogs. When needed (during hunting for example), they press their forelegs close to the body, the hind legs to the tail and drive themselves with an undulating movement of the body. For short distances they can even reach the speed of 12 km/h (7.5 mph). On occasion, they can stay submerged for 4 minutes, although the average duration of a dive is 20-50 seconds. During one dive they can swim 400 meters underwater. On the ground they may seem clumsy, but they are capable of running fast and covering long distances. Their tail is bulky, cylindrical on the top, thin in the end and plays a role in steering.
They can sometimes live for up to 10-12 years, but their average age is shorter. In captivity they have reached 22 years.
Way of life: Otters are solitary animals. Despite this, it is not uncommon to see 2 adult individuals stay together for a short period of time. Otters have a very playful nature; they can often be seen playing in groups or sliding in the mud of the riverside or in the snow.
Their habitats are rivers, lakes, swampy or boggy areas and seasides. Every otter has a territory along a water course or shoreline. They need the rich vegetation of the riverbanks as well as abandoned fox or badger holes that they can use for dens. Their hunting territories can overlap with each other to a certain degree: the area of a male can often contain the areas of several females. Otters mark their territories with their spraints on prominent places (stones that rise out of the water, tree stumps, bridges and points where rivers meet). They often use the same places for marking. Otters straying inside already occupied territories know from these spraints what the ‘master of the place’ had previously eaten and wether it is worthwhile to try looking for prey there. Although otters are territorial animals, conflict is rare – they prefer avoiding each other. The size of their hunting grounds along a river is 7 km (4.5 miles) for females and can reach 15 km (9 miles) for males. The hunting grounds are much smaller on lakesides and larger on seasides. The size of the hunting ground is determined by the availability of prey. Otters are not built in a very energy-efficient way; and their active lifestyle also requires much energy. This energy can only be provided by the consumption of a sufficient amount of food. An adult otter has to consume an amount of food that represents 15% of its weight; that means 1-1,5 kg (2-3 pounds) of fish per day.
Otters are most active during the evening and early morning when they hunt. They can move up to 10 km (6 miles) during one night. Most of their food consist of fish. Although they are able to catch large fish, they prefer those that are 20-30 cm (8-12 inches) and most often they consume even smaller ones that are easier to catch. From time to time, a large part of their nutrients consist of amphibians (frogs in the first place). According to a survey of otters living along the Mureş River, amphibians made up a larger part of their diet than fish. Occasionally, they consume birds, smaller mammals, crabs, snails, and shellfish. They eat the captured prey on the stones that emerge from the rivers or on the banks.
Reproduction: otters can reproduce in every season. Mating takes place in the water or on the ground. The time of pregnancy is 61-65 days, but it may be delayed for up to 9 months. They usually give birth to 2-3 young – sometimes up to 5 – in dens under the ground. Otters have a rather small number of offspring compared to mammals of the same size mostly due to the fact that they do not have natural enemies. Females raise their young alone. The mother teaches her young for a long period. They become independent at the age of 1 year. During this time, they learn fishing methods and get to know the places that are rich in fish. They also have to learn the technique of drying themselves: the main reason for death among the young is catching cold because of wet fur. They reach sexual maturity by the age of two. Most otters – according to Western European data – do not live for more than 3 years, becoming victims of traffic accidents, water pollution or starvation.
Otters and humans
Otters do not occupy such a prominent place in people’s beliefs as bears and wolves. Nevertheless, they appear in many people’s legends and tales like in the case of the Celts, North American Indians, Indonesian peoples, native Australians and in Northern peoples’ (Norwegians, Swedish, Danish) pagan religions that preceded Christianity. In Alaska, a bone statuette was found dating back to 800 A. D., portraying a half human – half otter creature – most probably a shaman.
Otters usually symbolize intelligence, skillfulness, playfulness and joviality.
From the dawn of time, humans have always appreciated the fur of otters; this is why they have systematically hunted them. Diverse artifacts and records talk about their importance. The first known otter representation that appears on a relief dates from 1500 B.C.. According to some records, beginning in 1500 B.C., the hunting of sea otters had a very important role in the life of the North American Indian tribes that lived on the shores of the Atlantic Ocean. The fur of otters, their skin, meat, bones and even their teeth were essential for these people. This eventually led to the fact that, around 200 A. D., whole settlements have been depopulated as a consequence of the extermination of sea otters.
There also are records from 600-900 A. D. – the period of the Tang dynasty – telling us that Chinese fishermen used trained otters to catch fish. Early European encyclopedias (1480) also mention fishing with otters. This method is still used, especially in the East.
The dark Middle Ages – just like in the case of wolves and bears – did not provide much that was good for otters. In 1556 there was a decree in England promising rewards for killing otters and ‘other harmful pests’. In yet another paper from England, the author mentions that otters had become so daring that “they attack the farmers sheep and the housewives’ poultry”.
In 1751, in the description of the Europeans’ first expedition to Alaska, Steller mentions that sea otters had lived there in great numbers. Beside the fact that it was very easy to capture them, their fur was marvelous and the meat of the young was very tasty. Mass extermination of otters for their fur started in 1792. The hunting of sea otters came to an end in 1911, with the convention for the protection of seals. Seals are also hunted for their fur, and sea otters were included in the convention by accident. In any case, this happened just in time, because, according to the estimates, world sea otter population at the time consisted of only 500-1000 individuals.
In the 1800s several articles were published in England about the fact that, in those rivers from which otters were exterminated, the number of fish worthless for fishing increased. According to an article that appeared in an English hunting review in 1946, otters do not cause serious damage in trout populations of creeks and rivers.
These days, the factors that threaten otters are river regulations (ruining their habitats and reducing the number of their prey), water pollution (detergents damage the impermeability of their fur), illegal hunting and traffic accidents.
Otters, as we have already mentioned, are on the top of the water habitats’ food chain, therefore all poisonous materials (like heavy metals) eventually pile up in their organisms. Therefore, otters are a sort of ‘indicator’: their presence or their health reflects the state of the habitat as well.
Otters in Romania
Previously, otters were hunted in Romania as well, mostly on the territory of the Danube Delta. In 1993, Romania joined the Bern Agreement. In accordance with this agreement and with law no. 103/1996 regarding hunting (completed by law no. 654/2001) the otter is a protected species. Its hunting is forbidden by law; nevertheless one can hunt them if in possession of a permit. Since otters can no longer be hunted, the interest towards them has ceased.
Practically, for more than ten years there are no data on the number of Romanian otters, nor on their distribution or the composition of their diet.
