The otter is the largest member of the mustelid family in Ireland, measuring over a metre in length, with a muscular streamlined body and a long, rudder-like tail. Over three- quarters of Ireland’s riverbanks, lakeshores and coastal areas have resident otters. Otters are very common in Ireland but water pollution has seen their numbers fall greatly throughout the rest of Europe.

Every adult otter, male and female have their own territory along lakeshores and rivers. The otter’s home is called a holt and the holt often features an under-water entrance. An otter has webbed feet to help it to swim. Otters are carnivores – their diet includes food like; eels, fish, frogs and often duck. The young are called cubs. Cubs are born with their eyes closed and they are covered in fur. At one month old, the cub can come out of the holt, and at two months old, the cub begins to swim. Otters leave home when they are about 12-15 months old and find a new territory. They can live for up to 16 years.

There is much existing mythology around the Otter. The Prose Edda manuscripts of Norse mythology tell us of the dwarf Ótr who could turn himself into an otter. Similarly, the Volsunga saga tells the myth of ‘Otter's Ransom’ or ‘Ottergild’, where the character named "Otter", could turn himself into an otter also.