Survey Leaflet
Irish Stoat Survey in Galway 2010
Species Irish Stoat
Facts about Irish stoats
- English name/Irish name: Irish stoat/Easóg
- Latin/Scientific name: Mustela erminea hibernica
- Number of young: Up to 12, called kits, born in early April
- Diet: Rabbits, shrews, rodents, birds, invertebrates and fish
- Habitat: Most habitats with sufficient cover — including urban areas — but occur most often in wooded areas where they readily climb trees
Distribution and status
The Irish stoat, a unique subspecies of stoat, is found exclusively on the island of Ireland and the Isle of Man. In contrast, the stoat species as a whole is widespread across northern Europe, Asia, and North America and has been introduced to New Zealand. Stoats similar to the Irish subspecies can also be found on the Scottish islands of Islay and Jura, as well as in parts of northwestern North America.
Very little is known about the overall population of Irish stoats. However, data collected during the recent Irish Stoat Citizen Science Survey (2023–2025) may provide new insights. VWT, in partnership with the National Biodiversity Data Centre (NBDC), the Centre for Environmental Data and Recording (CEDaR), and the University of Galway (UoG), is currently analysing 1,081 public submissions from the survey. The findings, set to be published in May 2025, hope to reveal the current distribution of Irish stoats across the island of Ireland
Irish stoats are usually, and mistakenly, called weasels in rural areas. It is in fact a distinctive stoat and a separate Irish sub-species.
Irish stoats have brown upper body fur, possibly darker than stoats elsewhere, but this has never been quantified. It has a white underside, and occasionally a white spot or two on the lips. Usually it has an irregular back-belly line between the brown back and the white underside. However, around 12% have straight back-belly lines, like stoats found in the rest of Europe. The tip of the tail is always black, a classic characteristic of stoats. It does not normally become white (ermine) in winter, thought to be because of the lack of sitting snow on the island. The females are much smaller than the males.
The Irish stoat is found wherever there is suitable cover and food. It is a good swimmer, surefooted climber and perfectly adapted for squeezing into small holes and burrows.
Irish stoats prefer areas with cover, such as stone walls, ditches, and hedgerows — and avoid open areas, where they run the risk of being eaten by foxes, cats, pine martens and birds of prey. They use features such as hedgerows and stone walls to move within the landscape.
The Irish stoat is a solitary and territorial animal and often uses the nests or burrows of prey as its own denning sites, lining the den with prey fur or feathers.
The Irish stoat is capable of killing prey several times its own size and its varied diet includes rabbits, rats, shrews, mice, voles, fish, invertebrates, birds and their eggs.
Irish stoats hunt systematically across micro habitats, for example climbing and searching most trees in woodland. It is also possible that fruit and insects may form part of their diet when other prey is not so available, and there are several reports of them predating and eating fish on seashores, which has led to a suggestions that they are originally coastal animals.
Mating takes place between the months of March and August with the young (known as kits) being born in the following April.
Male stoats are sexually mature at one year old but, amazingly, female kits are mated while still in the nest. However, due to delayed implantation, there is no further development of the embryos until the following spring when between 10 and 12 kits may be born. The kits remain with the mother until fully grown at around five months old.
Although little is known about the population size, the Irish stoat faces many of the threats facing other mammals, including habitat loss, predators, and road traffic.
The Irish stoat is predated by foxes, dogs, cats and pine martens, and is probably also taken by birds of prey such as owls and eagles. They are a frequent victim of road traffic and such accidents peak seasonally. The Irish stoat is protected under the Wildlife Act (1976) and Wildlife (Amendment) Act 2000.
VWT's work
Information leaflet
Guide to Identifying the Small Mustelids of Ireland
FAQs about Irish stoats
Irish stoats are often called weasels. However, weasels are not present in Ireland. If you visit Britain or mainland Europe, where both species are present, the main differences are size (stoats are larger) and weasels don’t have a black tip to the tail. But, confusingly, stoats, pine martens, mink, otters and badgers all belong to the Family Mustelidae, which is also known as the weasel family!
The Irish stoat, Mustela erminea hibernica, is a unique subspecies only found on the islands of Ireland and the Isle of Man. It differs physically and genetically from stoats found in Britain and Europe — the Irish stoat tends to be smaller, it doesn’t turn white in the winter, and the line dividing the chestnut-coloured upper fur and the creamy-coloured fur on its belly is usually irregular.
Fossil bones of the animal have been found in two caves in County Cork, with one set dating back between 27,000 and 35,000 years and a second set around 10,680 years ago. There is compelling evidence that the species survived the last Ice Age under the snow, making it one of our oldest mammal inhabitants, along with the Irish hare.
Stoats are often confused with other small carnivores in Ireland, including ferrets, American mink and the pine marten. Although similar in some ways, you could say ‘stoats are ‘stoatally’ different! All four species share the same long, thin body shape and short legs, but stoats differ in their much smaller size (far smaller than a cat), chestnut brown coat with creamy white underside, and the very distinctive black tip to their tail.
The black-tipped tail is the stoat's most distinctive feature, but it's not there just to look good. In an experiment conducted by Roger Powell using captive hawks and model stoats, it was observed that the models with black-tipped tails were less likely to be successfully targeted by the hawks compared to those with black spots in other areas or no black markings. This suggests that the black tip on the tail may draw away a predator’s attention from more vulnerable areas like the head and neck.
Stoats live in many habitats but are often seen darting across roads to dive into stone walls or hedgerows, which offer protection from predators. They’re active all year round, day and night, though colder days may keep them underground.
Stoats pose no significant danger to humans and pets like cats and dogs. Their natural behaviour is to avoid contact with people and much larger animals, such as cats and dogs. However, stoats can prey on birds such as chickens and take their eggs if given the opportunity. Making sure chicken enclosures are well maintained and free of gaps will prevent stoats from getting in.
Yes, Irish stoats are protected throughout the island of Ireland:
- Republic of Ireland: Wildlife Act (1976) and Wildlife (Amendment) Act 2000.
- Northern Ireland: Wildlife and Natural Environment Act (Northern Ireland) 2011
Your sightings are invaluable — If you see an Irish stoat, submit your sightings via the National Biodiversity Data Centre. By participating in Citizen Science, you’ll help fill critical knowledge gaps.