EURASIAN OTTER (Lutra lutra)

Biological/outstanding features

SIZE: 1-1.3m
WEIGHT: 7-9 kg
DIET: Fish (80%), birds, small mammals, frogs
GESTATION: 9 weeks
OFFSPRING: 2-3 cubs
HOME RANGE: 20-30 km river 3-4 km coast
PHYSICAL FEATURES: Short limbs, webbed feet and claws - Sensitive whiskers around snout to help detect prey - 2 layers of fur: a thick waterproof outer one and a warm inner one.
SPECIAL ABILITIES: The Eurasian otter has an acute sense of sight, smell and hearing. The eyes are placed high on the head so that it can see when the rest of the body is below water.
FACT: Although the otter is an exceptionally good swimmer and fish catcher, it can only hold its breath for 20 seconds as it dives for its prey.FACT: Otters are the only amphibious members of the weasel family

Distribution/habitat

DISTRIBUTION: Found in France, Spain, Greece, Scandinavia, Scotland and Turkey, but scarce in England. N.B. Other species of otter are found in North and South America, South Africa, the Middle East and Asia.
HABITAT: Lakes and rivers or rocky coasts.

The threats to survival and the conservation states of the Eurasian otter

CONSERVATION STATUS: Near Threatened.  

THE THREAT TO THE SPECIES: There are many factors that contribute to making the otter's life very hazardous. These include habitat destruction, both on land i.e. the building of roads and the loss of previously undisturbed riverbank systems, and in the water (particularly in the sea, as otters may be caught in fishing nets where they can ultimately drown).
Traffic injuries also pose considerable problems for otters, as new roads are built through their previously tranquil homesteads.
Pollution from pesticides, PCBs, mercury and oil can all be severely damaging to the otter's health, when found in traditionally clean streams.
But by far the greatest threat in our area is the risk of an oil spill. The Minch waters between Skye and the Outer Hebrides is still a major oil tanker route and it is argued by many that a spillage is just waiting to happen. The Exxon Valdez killed thousands of sea otters and otters were also effected by the Braer disaster in Shetland.

Communication and social structure of the Eurasian otter

COMMUNICATION: Otters communicate using vocal expression such as whistles, birdlike twittering and spitting.  They can also communicate using spraint. Over 100 different scent components of otter dropping have been identified. About 17 of these are thought to contain information on sex, age and even individual recognition, which can be used by other otters.
SOCIAL STRUCTURE: Otters tend to live alone, except during mating and for a short time after the cubs are born. The young will stay with the mother for approximately 13-15 months.

Life History

Although otter cubs can be born at any time of the year, we find there is a definite preference for spring and again in late autumn. On average 2-3 cubs are born, weighing only 40g, covered in a pale grey fur and with closed eyes. They develop slowly and the eyes will open in five weeks. At seven weeks they will start to run and take solid food. It is at this time that they will venture out of the holt to toilet outside but they will not go much further until they are 10 weeks old and they are fully weaned at 14 weeks.

Strangely enough, young otters are not natural swimmers and the fluffy coat of the young makes it difficult, so they are often dragged into the water by the mother at 16 weeks old. They learn quickly and soon catch their own food. However they are still dependent on Mum and will stay with her for over a year, on many occasions even up to 15 months.

The juvenile cubs will start to disperse at 14 to 15 months and venture into new areas to find their own territories. Survival in the harsh environment on their own is very difficult as they try to find a territory and good feeding grounds.

Mating takes place at anything from 17-20 months and the male picks up the scent of the female in season and goes looking for her. The two otters chase each other along the shore, disappearing into the sea and diving, swimming and rolling together before mating takes place. The male often stays close to the female for about a week before venturing on to pastures new.

To survive in the wild, however, is not easy, particularly for a Carnivore and the otter will be lucky to reach the age of 4. However, there have been instances of otters living from 8-12 years, although possibly only one or two in a hundred will survive until this sort of age.

Distribution of the Eurasian Otter (Lutra lutra)

Data based on Otters and Action Plan for their conservation (IUCN 1990) and world otters (IOSF 2005)