European Otter - Behaviour and Reproduction

Behaviour and Reproduction

European otters are strongly territorial, living alone for the most part. An individual's territory may vary between about one and 40 kilometres long (about one-half to 25 miles), with about 18 km (about 11 miles) being usual. The length of the territory depends on the density of food available and the width of the water suitable for hunting (it is shorter on coasts, where the available width is much wider, and longer on narrower rivers). The territories are only held against members of the same sex, so those of males and females may overlap.Mating takes place in water. Eurasian otters are nonseasonal breeders (males and females will breed at any time of the year) and it has been found that their mating season is most likely determined simply by the otters' reproductive maturity and physiological state. Female otters are sexually mature between 18 and 24 months old and the average age of first breeding is found to be 2.5 years old. Gestation for L. lutra is 60–64 days, litter weight when being compared to the female body mass is about 10%. After the gestation period one to four pups are born, which remain dependent on the mother for about 13 months. The male plays no direct role in parental care, although the territory of a female with her pups is usually entirely within that of the male. Hunting mainly takes place at night, while the day is usually spent in the European otter's holt (den) – usually a burrow or hollow tree on the riverbank which can sometimes only be entered from underwater. Though long thought to hunt using sight and touch only, evidence is emerging that they may also be able to smell underwater - possibly in a similar manner to the star-nosed mole.