Eurasian Otter – Lutra lutra

Eurasian Otter – Lutra lutra – Madra uisce/Dobhar cú – Dyfrgi

The Eurasian Otter (Madra uisce) is found across Asia, Europe, and the North of Africa. Fortunately for residents and visitors of Iveragh & Pen Llŷn, this charismatic species can be found in the coastal areas and waterways of both peninsulas. Having said this, you will certainly need a keen eye (and just an ounce of luck) to catch a glimpse of one. This is especially true, as the Eurasian otter is a solitary species that is nocturnal in nature, with most of their activity occurring around dawn and dusk. 1

Photo of our native Eurasian otter running by Knowledge Gatherer, Linda Lyne.

The otter belongs to the weasel family ‘Mustelidae’. This is a group of carnivores that includes Ferrets (Firéad), Stoats (Easóg), Mink (Minc), and Badgers (Broc). 2

Interestingly, the otter’s Irish and Welsh names all speak to the species’ semi-aquatic lifestyle. In Irish, the two most common names for the otter are ‘Madra uisce’ (modern Irish) and ‘Dobhar cú’, which translate to ‘water dog’ and ‘water hound’. The Welsh translation of otter is ‘Dyfrgi’, which has a similar meaning of ‘water dog’.

Appearance, adaptations and comparison to the Sea otter:

The Eurasian otter is quite recognizable, especially when seen on land. Individuals usually range in length from 90 to 130cm from head to tail, weighing between 7-12 kilograms. 3, 4, 5 This means that they are one of the largest mustelids you will encounter in Ireland and Wales. Their thick brown fur is darker on top than it is on the underside. Their large size, long whiskers, thick fur, and tapered tail help in their identification.

Although our native species, the Eurasian otter (Lutra lutra), is often seen in the sea and in brackish waters (a mix of salt and freshwater), they are dependent on having access to clean sources of freshwater to keep their fur clean; this maintains the fur’s insulative properties which are important for heat retention. Their webbed feet are another adaptation to their semi-aquatic lifestyle, the webbing helps them while swimming and while moving across wetter soils. 3

Our native Eurasian otter walking along the shore, recorded by Linda Lyne.

Our native species should not be confused with the true ‘Sea Otter’ (Enhydra lutris), which is an entirely different species found exclusively in the North Pacific Ocean. They are very frequently featured in documentaries, bobbing on their backs above the Kelp (Ceilp) forests along the west and northwest coast of the United States. This species is highly adapted for life in coastal marine habitats and can spend their entire lives in the ocean. The Sea otter is also far larger than the single species present in Ireland and Wales, weighing anywhere between 14 to 45 kilograms. 6, 7, 8

A raft of Sea otters in Morro Bay, California.

Ecology, habitat and diet:

Eurasian otters live close to rivers, streams, lakes and coastal lagoons that provide them with access to freshwater, plentiful food sources, and terrestrial habitats with plenty of cover – used to construct ‘couches’ and ‘holts’. Couches are the resting places used by otters. They are located above-ground, often on islands, in dense reed beds, or in other bankside areas dominated by vegetation or scrub. Holts are the below-ground breeding dens of otters where cubs are raised. They are usually well-covered and occur close to, or within, riverbanks in caves, crevices, rock-piles, or amongst the root-systems of bankside trees. 1, 3

Otters are a highly territorial species, and they mark their territories with droppings known as ‘spraints’. These spraints are described as ‘sweet-smelling’, often compared to the scent of mown hay or jasmine tea. Droppings can be found deposited on rocks, on ledges, or at frequently used resting or fishing sites. Keeping an eye out for these spraints is a good way of detecting whether otters are actively using particular stretches of coast or river. The size of an otter’s territory depends on the availability of food resources and shelter along their stretch of river or coast. Otters living in areas where food is plentiful can have territories as small as 2km, while those living in areas where food is more limited may have territories of 20km, or more. 3, 4, 9

The most important food sources for otters are fish [Sticklebacks (Garmachán), Trout (Breac), Salmon (Bradán), Eels (Eascann)], crustaceans and molluscs [Crabs (Portán), Crayfish (Cráifisc), Shellfish (Sliogiasc)].

Amphibians [Common Frogs (Frog)] become an important food source for otters in Spring, while birds and small mammals are also eaten occasionally. 1, 3, 4

Myths, legends and folklore surrounding the otter:

An old Irish tale surrounding the otter describes the ‘dobharchú’ as a creature that is part-dog and part-otter. Although likened to an otter it was said to be far larger and much more vicious. It was described as having entirely white fur, with black tips on its ears and a black cross on its back. 10

A headstone can be found in Glenade, Co. Leitrim with an image of the dobharchú. It is said that the headstone belongs to that of a woman who was killed by the animal in 1722, while washing clothes at Glenade Lake. When she did not return home that evening, her husband went in search of her only to find the dobharchú asleep on her body. 11, 12, 13, 14

A note from Linda Lyne, Knowledge Gatherer, working in Iveragh:

Many a time I have eagerly followed a tantalising stream of bubbles coming from below the water surface – only for a Cormorant (Broigheall) to pop up. No offence to cormorants, but what I was really hoping for was the whiskered, round eyed face of an otter. These bubble streams can sometimes be a sign that an otter is moving along the bed beneath the water, using their whiskers to sense movement from hidden crabs or fish. Otters that forage along the coasts of Iveragh are a hardy bunch. While some stick to the seaweed rich shorelines or estuaries, others may venture further upstream.

There are many waterways and stretches of coast in Iveragh where you may catch a glimpse of an otter: Valentia Island, Sneem and Portmagee to name a few. Encountering an otter rolling and diving in our impressive Iveragh waves will stop you in your tracks. It is quite a sight to behold, their streamlined shape, twisting and ducking beneath the frothy crests – often while crunching on prizes they have collected from the seabed.

And if you are one of the lucky ones, sightings can be submitted to the National Biodiversity Data Centre: Recording System :: Mammals (

An otter recorded swimming and diving off of Iveragh’s coastline, recorded by Linda Lyne.

A note from Ben Porter, Knowledge Gatherer, working on Pen Llŷn:

It’s a soggy March morning on Pen Llŷn, with a dragging north wind adding to the chill of the air. Walking along the harbourside of Pwllheli marina, I catch sight of a small party of Herring gulls (Faoileán scadán) mobbing an unseen character in the sea. I stop in my tracks, scanning the water frantically beneath the gulls with my binoculars. Nothing. I stand stock still for ten minutes, straining my eyes for a sign of any life at the water’s surface. Then suddenly, a distinctively sleek, dark shape breaks the water’s surface, pops its head up for a matter of seconds - then slips silently beneath the surface, making for the pontoons of sailing boats moored nearby. AN OTTER!!! I could barely believe it. My hunch had been correct, and what I had just witnessed was my very first sighting of this elusive creature on Pen Llŷn: the Dyfrgi (literally, ‘water dog’ in Welsh).

It’s hard to believe otters inhabit the waters all the way around Pen Llŷn’s coastline, especially considering how few sightings occur and how difficult they are to spot here. And yet, signs of otters (such as their ‘spraints’, and their ‘holts’) have been spotted in virtually each of our small river systems – the Daron, the Soch, and the Dwyfor, for example. One of the main reasons so few sightings occur is due to their nocturnal nature: they tend to become most active under the cover of darkness. But, as I had witnessed that wet March day, you might occasionally be lucky enough to catch a glimpse of its ghost-like form breaking the water surface during daylight hours.

So, keep your eyes peeled whilst around Llŷn, and don’t forget to submit any sightings to the North Wales recording centre: Cofnod - North Wales Environmental Information Service | Home.


1. Lutra lutra (Eurasian Otter) (

2. Mustelidae - Wikipedia

3. Otter Leaflet 4 (

4. Eurasian otter - Wikipedia

5. Otter – A guide to Irelands protected habitats & species (

6. Sea Otters ~ MarineBio Conservation Society

7. Sea otter | mammal | Britannica

8. Sea otter - Wikipedia

9. Otter | The Vincent Wildlife Trust

10. ‘Ireland's Animals - Myths, Legends and Folklore’ by Niall Mac Coitir.

11. Tohall, P. (1948). The Dobhar-Chú Tombstones of Glenade, Co. Leitrim (Cemetries of Congbháil and Cill-Rúisc). The Journal of the Royal Society of Antiquaries of Ireland, 78(2), 127-129. Retrieved May 21, 2021, from

12. The tale of Leitrim's own Loch Ness Monster - the Dobhar-Chú - Leitrim Observer

13. Dobhar-chú - Wikipedia

14. Does prehistoric otter explain Dobhar-chú myth? -

15. Cofnod - North Wales Environmental Information Service | Home