Ermines vs Weasels: Difference and Comparison

It is quite common for people to get confused between an ermine and a weasel, as they are both very similar. They are animals belonging to the same family.

Both are called weasels; however, there are distinct differences between the two that set them apart, and thus, they are regarded as different species.

Key Takeaways

1. Ermines are a specific species within the weasel family, known for their distinct white winter coat.
2. Weasels are a broader category, including various species with a more uniform brown or reddish-brown coat.
3. Both ermines and weasels are carnivorous mammals, but ermines tend to inhabit colder climates, while weasels can be found in various environments.

Ermines vs Weasels

The difference between Ermines and weasels is that they are two different species of animals. They belong to the same family and genus as Mustela but are two entirely different species. Many characteristics like size, colour, habits, and other features set them apart from each other.

Ermines are the common name for the animal with the scientific name of Mustela erminea. 

Mustela erminea, or ermines, are small squirrels-like animals with long tails and slightly larger bodies.

They are soft brown-coated animals with black-tipped tails with a carnivorous habit. They also change colour in the winter.

Weasels are the common name for the animal with the scientific ne of Mustela nivalis. Mustela nivalis, or weasel, is also a small squirrel-like animal, much like ermines.

They have similar habits and habitats but differ in their coat colour. They have a coat of reddish-brown colour that also changes in the winter.

Comparison Table

Parameters of Comparison	Ermines	Weasels
Size	Ermines are larger than weasels ( 7-13 inches).	Weasels are smaller in size (8 inches).
Weight	Ermines weigh more than weasels.	Weasels being smaller weigh less than ermines.
Tail	Ermines have a longer tail with a black tip.	Weasels have a shorter tails with no distinctive colouration.
Coat	Ermines in the summer have chocolate brown coat and white in the winters.	Weasels have a reddish brown coat in the summer and white in the winters.
Gestation	Ermines have a longer gestation period than weasels which is almost thrice the time.	Weasels have a shorter gestation period than ermines.

What is Ermines?

Ermines are mammals that belong to the family of Mustelidae. They are small, soft-bodied animals belonging to the Genus of Mustela. Ermines are the common name of the species Mustela erminea.

They are also known as stouts, short-tailed weasels, northern stouts, or even Bonaparte weasels.

Ermines can be distinguished from the other five species of weasels by the colouration of their fur and size. Ermines are chocolate-brown coloured animals.

Their fur is soft and changes colour in the winter to white. In the summer, the chest and stomach areas remain white. The characteristic of an ermine is its tail.

An ermine’s tail is almost one-third of its body and has a black tip. This back tip is more prominent in the winter when the animal turns white.

It is around 7-13 inches in size and weighs around 120-150 grams. It’s a small animal, yet it is bigger than the least weasel. Also, their larger size contributes to their weight than the weasels.

They are active animals that feed on insects, invertebrates, bird eggs and other small animals. They also are common prey of cats, foxes and badgers.

They are abundantly found in the United States. They also give birth to many young at once that can be from 3-18 in number in 280 days.

What is Weasels?

Weasels are also mammals that belong to the family of Mustelidae. They are small, soft-bodied animals belonging to the Genus of Mustela.

Weasels are the common name of the species Mustela nivalis. They are also known as lesser or least weasels. 

Weasels can be distinguished from the other five species of this genus by closely examining their fur colouration and size.

Weasels have reddish-brown coloured fur, which is not as soft as ermines. Also, this colour lasts only in the summers and in the winter, they change the colour of their fur to white.

At this stage, they look pretty much like an ermine except for the fact that they do not have a black tail tip like that of an ermine.

They are less than 8-9 inches in size and also weigh much less than ermines. However, they do have a longer tail than ermines, which is almost two-thirds the size of their body size.

They are also very agile animals with similar feeding habits, but due to their small size, they fall prey to a larger set of animals, including predatory birds like hawks and eagles.

They are also very abundant. They give birth in smaller batches of 5-6 young in a shorter reproductive period of about a month and 10 days.

Main Differences Between Ermines and Weasels

1. Ermines are commonly called stouts, while weasels are the common name for least weasels.
2. Ermines being larger, have a different set of predators than weasels, which are more susceptible to a larger number of predators.
3. Ermines give birth to younger than weasels and also have a larger reproductive cycle of about 280 days in comparison to 34-37 days of weasels.
4. Ermines have a black-coloured tail tip that is very prominent in the winters when their fur turns white, while no such tip colouration is present in the least weasels.
5. Ermines also tend to have softer fur than weasels and, thus are more commonly hunted than weasels.

References

1. https://www.jstor.org/stable/1375093
2. https://academic.oup.com/jmammal/article-abstract/66/4/745/848104

Last Updated : 14 June, 2023