Otter
Lutra lutra
Madra Uisce / Dobharcú
What group of mammals does the otter belong to?
Both Irish names for the otter mean water dog or hound, but the otter is actually the largest member of the mustelid family in Ireland. This family also includes the badger, stoat, pine marten & mink. The otter is up to 1.2 metres in length, with a muscular streamlined body and a long, rudder-like tail.
How common are otters?
In Ireland, very common actually! More than 90% of riverbank, lakeshore and coastal areas have resident otters. We know this because of the presence of their droppings (spraints) which mark their territories. But the story over much of Europe is very different, where the otter is in serious decline, due to water pollution and over-development. Otters are mostly nocturnal, which is why they are rarely seen here by most people.
Is the otter native to Ireland?
Since otters are strong swimmers and live on many offshore islands, we can assume that they are most likely native to Ireland, and reached here shortly after the Ice Age.
Are otters social animals?
Like most mustelids, otters tend to lead solitary lives. Each adult otter holds a territory along a lakeshore or river. The size of the territory depends on food supply, and those of males & females often overlap. Within each territory are a number of burrows called holts. Each holt has several entrances, some hidden under water. Otters also have ‘couches’ to rest on above ground, and slides which they use to slip into the water.
How is an otter adapted to water?
Like many animals that swim, an otter has webbed feet. The body is streamlined and the tail is strong for propelling through the water. There are 2 layers of fur; a dense coat of underfur that traps air to keep the otter warm, and an outer layer of guard hairs for waterproofing. The eyes are on top of the head for seeing above the surface, and the long stiff whiskers are used for finding prey in murky water.
What do otters feed on?
Otters find almost all their food in the water. They are carnivores, with fish being the main prey. Eels are a favourite, but any fish that occur in enough numbers are taken, including trout, salmon, roach & perch. Frogs are eaten in marshy areas, and waterbirds such as ducks are occasionally taken. On the coast, otters occur in higher densities, feeing on the abundance of prey in rockpools, such as crabs and wrasse.
Do otters have any predators?
As carnivores, otters are at the top of the food chain, so they have no predators. They are too big to be preyed on by other Irish mammals. Otters were hunted by humans in the past, but are now protected under the Wildlife Act.
Do otters hibernate?
Otters have no need to hibernate, as their food is available all year round.
When are baby otters born?
Courtship takes place in spring and summer, then the male and female go their separate ways. The young cubs are born in the holt, covered in fur but with their eyes closed. They are fed by their mother until 4 months old, stay with their mother for up to a year. Otter cubs are very playful, and even adults enjoy play.
How do I look for otters?
Otters are very secretive and hard to find. But look out for their droppings (spraints) on rocks near rivers and lake shores. You may also see the slides that otters use to get into the water. Often all you will see of the otter itself are a few ripples as it slides into the water on your approach. Your best chance of seeing otters is in the early morning and on the coast.