Written by Nicklas Iversen | Last edited 27. August 2021

The stoat, or ermine, is one of the most common mustelids in Norway and is found pretty much throughout the country. The stoat is a skilled hunter that eats rodents with amazing efficiency!

Get to know the stoat

Stoats are small predators that belong to the weasel family and probably have the widest distribution of any mustelid in Norway. This little carnivore specialises in hunting mice, but will also kill other small animals that it comes across. It is found in many different types of habitat throughout the country and was much sought after for it’s fur for a long time.  

It is both a good climber and a good swimmer. With it’s ability to see well in the dark, it prefers hunting at night or at dusk.  

Stoat physiology

The stoat has a long, muscular body with relatively short legs. It’s head is quite small and it’s entire body is covered with dense fur. In winter, the stoat’s coat is white apart from the tip of it’s tail, while it’s summer coat is brown on top and white or creamy yellow underneath. The tip of the stoat’s tail is black regardless of the season.  

It can be difficult to tell the difference between a small stoat and a least weasel, as they are very similar even though the stoat is distinctly larger. A good way of telling them apart is to look at the tail: the stoat’s tail is much larger than that of the least weasel and also has a black tip. If you spot a stoat or weasel without seeing the tail, it can be impossible to tell the difference.  

How does the stoat live?

Stoats are found in the majority of habitat types in Norway, but stay put once they have found a place to live. They establish a territory and, like many other territorial species, will defend it against intruders. The male’s territory is much larger than the female’s, which can also be completely or partly within the male’s territory.  

Stoats live in dens, and will make them in cracks in rock, tree trunks, screes or the like. There can be a handful of different dens in each territory.  

The territory is marked with urine, scent secreted from the anal gland and faeces. Although the males typically chase other males off, they may allow both young animals and females to live on the fringes of their territory, for a while at least.  

What does the stoat eat?

The stoat specialises in hunting and eating mice, but will also consume young hares, birds, earthworms, frogs, a few berries, insects and bird eggs. If prey is plentiful, it likes to kill more than it needs and store the food for later. It is a capable hunter that can easily kill prey a good bit bigger than itself, so even slightly larger prey animals like ducks and hares are not safe from a hungry stoat.  

If stoats live in the vicinity of a built-up area, they will eat from rubbish bins that are not well secured, although this is rarely a problem here in Norway.  

Photo: Kentish Plumber med CC BY-NC-ND 2.0-lisens

Stoat reproduction

Breeding season for stoats is between May and July, when the males will go about trying to mate with as many females as possible. They will also enter the territory of other males, so there may be some conflict, but both males usually emerge from the encounter unharmed.  

Although the breeding season is in early summer, the young are not born until April or May of the following year. This is due to a phenomenon called delayed implantation, with the fertilised egg not being implanted in the uterus until conditions are most favourable for having young. Once the egg is implanted, stoats are pregnant for about 30 days before giving birth.  

Many females will be fertilised when they are between just five and eight weeks old! However, they will not give birth until they are about a year old.  

Before the females give birth, they make a nest, which can be built in virtually any cavity imaginable. They often use rock heaps or hollow trees. The size of the litter depends on how much food is available, so in a so-called rodent year they can give birth to more than ten cubs. In other years, when mice and other rodents are not as plentiful, they will give birth to between five and ten cubs instead.  

The cubs are blind and completely dependent on their mother for the first six weeks of life, but when they open their eyes at this stage, they grow quickly! Once their eyes are open, they soon join their mother outside the den on hunting expeditions and stay with her until late summer. In late July or early August, the cubs are large enough to hunt by themselves. They will then leave their mother and her territory to find a place of their own.  

Where are stoats found in Norway and around the world?

Stoats are found throughout Norway and probably have the widest distribution of any predator. There is no part of the country where stoats have not been observed, but their population density is probably lower in the far north.  

Stoats are also found in many other countries apart from Norway, as they have what is called circumpolar distribution. This means that they are found throughout the northern hemisphere, in Europe, Asia and North America alike. It is also a commons species in all these regions.  

Challenges facing stoats

Stoats have a number of natural predators, and both birds of prey, like golden eagles or owls, and red foxes can kill them given the chance. The larger predators can take stoats too, although they rarely attack them.  

They are not particularly vulnerable to being killed by humans, and neither traffic nor hunting is a significant cause of death for them. There are, however, other problems such as food shortages, which often limit how long they can live, as it can be difficult for a stoat to find enough food to survive in years with poor rodent stocks.  

Photo: Kentish Plumber med CC BY-NC-ND 2.0-lisens

Learn more about the stoat

There is a lot of good information on the stoat and we can recommend the following sources for further reading: 

We have also used them as sources for our information page on the stoat. 


This article has been written by Nicklas Iversen, a former nature guide for Visitor Centre Carnivore Flå.  

Photo: Kentish Plumber med CC BY-NC-ND 2.0-lisens