THE OTTER

Eurasian otter (Lutra lutra)

The Eurasian otter is a carnivorous territorial mammal, of the family of the mustèlids, and the greatest mustelid of Catalonia.

It was originally present in Europe and some areas of the north of Africa, but at the beginning of the twentieth century, the destruction of their habitats, the contamination, the decrease of the populations of fishess and crabs, the hunt and the overexploitation of the river, made them go to more solitary and savage areas. In Catalonia we find them at the rivers of the Pyrenees and the Pre-Pyrenees.

Until 1973 was a legally persecuted and captured species.
Now, is a protected and classified species: it cannot be caught, captured or disturbed. Thanks to this protection, today it is present in more regions of theterritory.  Between 1995 and 2001 the otter was reintroduced to the conques of the Muga river, the Fluvià and the Natural Park of the Aiguamolls de l ‘ Empordà.

The otter is a bioindicator of the quality of our water.
Its preservation implies the quality of our rivers. Take care of them!

 

Where he lives? It is a water animal.

They can live in all kinds of fluvial and lacustrine environments and even in coastal and marine habitats. The otter needs clean water, abundant food, vegetal coverage and a place to hide and rest.

The density of the otter population decreases as the mountain height raises. In the Pyrenees, above 800 meters, the density is minimal and only one specimen is found every 5-20 km. Although it is a scarce and difficult to see animal, during the months of defrosting (April-May) it is easier to see some specimens, since they are now in wetlands, slow rivers or banks of marshes … like the lake of la Torrassa!

How is their Anatomy of an experienced swimmer

Adult females measure between 95 cm and 110 cm from the snout to the tail end and weigh between 4.5 kg and 7 kg. The males measure between 105 cm and 120 cm and think between 6.5 kg and 10 kg. They have a very dense coat, with a more or less dark brown color, but the cheeks, throat and belly are lighter, sometimes almost white.

Its anatomy is perfectly adapted to the aquatic environment: hydrodynamic structure, palmed feet, long, flattened tail that acts as a propellant inside the water, insulating coat … It has its flattened head with the nostrils, eyes and ears on the top. Thus they can continue with their functions without removing the head of the water.
The ears are small, round and covered with hair, and they can be closed hermetically during immersion.
The tactile vibrissons of the face and arms allow them to move and capture his prey in turbid waters, even in total darkness.
They have a lot of hearing and smell, and their sight during the dive is very good.

When they swim they do it as the dogs and for diving they are propelled with fast undulations of the rear half of the body breathing every 20-30 seconds.

They communicate through whistles, screams that reminiscent of human laughter and a kind of sneezing. They mark their territories with feces located in places conspicuous for the rest of otters.

How do they reproduce? Blind for a month.

The otter is a solitary species. Males and females only meet to reproduce. After mating, males scorn off their offspring. Therefore, when groups of otters are seen, it is usually females with young.

They can mate throughout the year and do it in the water. When it is time, the female builds a nest made from grass, moss and leaves in a cloak room. The period of gestation of the otters is 9 weeks and a couple of children are born. This small offspring is intended to guarantee the survival of all youngsters.

The young are born blind and take 4-5 weeks to open the eyes. In the first contact with the water, the female loads them to her shoulder and takes them to the center of the river, where she submerges them and lets them swim alone to the shore under their supervision.
The mortality rate is quite high during its first two years of life. After two years, they reach sexual maturity.

The otters in freedom can get to live between 12 and 16 years.

What does the otter eat? Her favorite dish is fish.

The activity of otters is mainly nocturnal, probably due to human pressure. Daily food needs are between 12% and 15% of their weight and they need from 40 grams to 80 grams of food per kilometer and day.

They eat mainly fish (95%), and specifically here in the Pyrenean rivers the common river trout and other introduced fish. They complete their diet with river crabs, water snakes or other small amphibians.They also eat micromammals, birds, reptiles, insects and molluscs, although in a smaller proportion.

They hunt preys by attacking them from below, capturing them with their mouths or using their forelegs.

The otter has always been considered an important impact on fishing, but it has been shown that the otter adjusts its own population according to the availability of food. In addition, since they also consume predators of fish such as water snake or ichthyophobic fish, the impact on fishing is minimal.

Otter legends and myths.

Due to the ability they have to stand on both legs and to manipulate objects with their hands, the old Europeans believed that the otters were a god disguised as an animal that lived on Earth to see how humans treated them.

In ancient Persia, the otter was known as a totally respectable “dog of water”. They severely punished any person who hunted or killied otters.

The Scottish legend of the “otter kings” explains that, when these creatures were captured, they had the power to grant any desire to the capturer in exchange for their freedom. In addition, their skins were greatly appreciated both for the ability to make the warrior invincible, and to protect him from drowning. They only had a weak point in a small area located below the chin.

Taxonomy: Lutra lutra, Linnaeus, 1758

Bibliography:

  • Pla de Conservació de la Llúdriga a Catalunya – (Documents dels Quaderns de Medi Ambient, 6). Generalitat de Catalunya. Departament de Medi Ambient. Setembre 2001
  • Ruiz-Olmo, Jordi. Els Grans Mamífers de Catalunya i Andorra. Barcelona: Lynx Edicions, 1995
  • Castells, Álvaro; Mayo, Manuel. Guía de los mamíferos en libertad de España y Portugal. Madrid: Ediciones 62
English

Amb el suport de: Actuació cofinançada per l'operació 04.04.01 del FEADER ("Actuacions en espècies, hàbitats i paisatges")