Mustelids in Europe

Part II

Species Identification

As an addition to the article about Mustelids in Europe, this will give you more information about the mustelids on a species level and will help you with species identification. What follows is an overview of the members of the mustelid family occurring in Europe. Definitely, in the smaller mustelid species, males are significantly larger than females. Each species will be briefly described with attention for identification and how to distinguish between related species. There will be links to observado.org for pictures and IUCN Red List for more information, distribution and images about the species. But feel free to google more if you get additional questions.

Stoat versus weasel

  • Underparts whitish (from throat to tail)
  • Length without tail between 15 to 30 cm

(Least) Weasel – Mustela nivalis

  • Length of the tail more or less same length as hind legs
  • Size of a rat
  • Border between underparts and upperparts is uneven wavy (sometimes straight line between upperparts and underparts and white feet)
  • Brown dots throat and around mouth
  • No black dot on tail

Observado.org
IUCN species information

Stoat/Ermine – Mustela erminea

  • A little bit larger than weasel
  • Tail at least 1.5x the length of hind legs
  • Tails is also bushier with black dot (sometimes black end/dot is gone as a result of predation)
  • Line between underparts and upperparts is straight
  • No dots on throat
  • Ears with light borders, more visible than Weasel

Observado.org
IUCN species information

Winter & summer coat
The black tail tip of the ermine remains black during winter. Potentially to attract the attention of predators, so they will go for the tail. Weasel ‘s tail is potentially too short for this strategy. This phenomenon is also not occurring everywhere. In the (Least) Weasel, individuals in Belgium and the Netherlands are very rarely seen in white. It is believed this ‘colour changing’ line is Somewhere in the Netherlands & South England.

 

Eurasian Polecat, Ferret, Marbled Polecat, & Steppe Polecat

  • Only white on the head, body more darkish (exception for Marbled Polecat)
  • Length without tail between 35 and 45 cm
  • Ears with a light border
  • Tail and legs darker than body
  • Undercoat light

Eurasian Polecat – Mustela putorius

  • White around nose and second circle behind eyes. Distinctive mask
  • In general, darker face compared to other species of Polecat
  • Obvious buff-yellow underfur on the sides and neck.

Observado.org
IUCN species information

Ferret – Mustela putorius furo
This is believed to be a domesticated form of the Eurasian Polecat.

  • Smaller and slimmer than Eurasian Polecat and Steppe Polecat.
  • Possible crossing Eurasian Polecat and Ferret
  • Ferret usually lighter in colour and not very distinctive mask
  • Light nose

Observado.org

Steppe Polecat – Mustela eversmanii

  • Distribution: Eastern Europe to Russia.
  • Similar to European Polecat, but longer body with a lighter, yellowish to light brownish coloured fur
  • Head is white with grey-brown spots around eyes and ears (so called mask).
  • Because of lighter colour, mask is less prominent as in Eurasian Polecat
  • Paler face and fewer dark guard hairs over the body than Eurasian Polecat

IUCN species information

Marbled PolecatVormela peregusna

  • Only in south-east of Europe
  • Spots, easily distinguished from other species
  • Dark coloured with light yellow to orange-yellow irregular spots on back
  • White around the snout, white circle around the face.
  • 3 yellow or yellow-white stripes in the neck
  • Darker tail point

Observado.org
IUCN species information

Beech Marten versus Pine Marten

  • Throat and chest are white or yellowish
  • Underparts dark
  • Length without tail around 50 cm
  • Throat colour yellow versus white is not a reliable characteristic to distinguish these 2 species

Beech Marten – Martes fiona

  • Legs and tail darker than the body, head slightly paler.
  • Ears rounded and smaller, more on the side of the face, edges can be lighter
  • Head is flatter and relative wide
  • Nose top light and pink
  • Foot soles without hair
  • Underfur light (white)
  • Throat has a distinctive white or cream patch that often extends down the front legs
  • Tail is a bit longer compared to Pine Marten

Observado.org
IUCN species information

Pine Marten – Martes martes

  • Body and head brown, more uniform colour
  • Ears large and angular, clearly prominent, more on top of the head, light (yellowish) edge
  • Head more round and relatively small
  • Nose top darker and brown
  • Foot soles with hair
  • Underfur darker (grey)
  • Tail looks ‘bushier’
  • Definitely in the dark in the headlights of the car, this underfur ‘shining through’ is a quite good way to distinguish.

Observado.org
IUCN species information

Check out the pine marten camera trap footage in this posts about Urban Wildlife in Belgium, in the second story (Camera trapping in Oelegem) there is a stone marten as well.

European Mink vs. American Mink

  • Darker than Polecat species
  • Only white around mouth/nose
  • Length without tail between 35 and 45 cm
  • Brown, dark brown, to black
  • Part of population white spots on throat and chest

European Mink – Mustela lutreola

Very limited distribution (relict populations in southern France – northern Spain, Russia and northern Baltic states (Belarus, Estonia, Latvia), and Romania (Danube delta).

  • White around snout, on both upper and lower lip (chin)

IUCN species information

American Mink – Neovison vison

  • Only white on lower lip (chin)

More related to the American weasels than to European Mink.
Classified in its own genus with the now-extinct Sea Mink.

Observado.org
IUCN species information

Otter – Lutra lutra

They can travel several kilometres overland from one body of water to another. They are excellent swimmers and can stay submerged for as long as five minutes. Otters find most of their food in water, but they sometimes also eat small mammals and birds. They are adapted to the life in and around the water. Their eyes have modified to be able to see underwater, and they blow out air and suck it in again to be able to smell underwater.

Otters are larger than mink, with a longer head and a thick tail. They are uniform (light) brown with greyish throat. They have a similar size as a beaver, but beavers are rodents (so don’t eat fish) and they have a flat tail, whereas the tail of an otter is round.

Observado.org
IUCN species information

Eurasian Badger – Meles meles

Eurasian badgers are very characteristic and difficult to confuse with other species of the mustelid family. They could be potentially mixed up with a Raccoon or a Raccoon dog in areas of overlap. Eurasian Badgers have distinct colour markings such as greyish dorsal fur, and prominent black and white head stripes. Their body is silvery-grey with black legs.

Unlike most mustelids, Badgers walk with their feet flat on the ground. (more like bears, their tracks also look like small bear prints). They have small eyes and ears. This is an adaptation as they spend quite some time underground. Eurasian Badgers are living in an elaborated burrow system, so called setts. If not disturbed, they use the same sett year after year. Their favourite food is earthworms, but they forage for anything eatable.

Observado.org
IUCN species information

Wolverine – Gulo gulo

  • Bear like head
  • Bushy tail
  • Short and powerful limbs
  • Body typically dark brown with some rusty-brown to blond part from shoulder to the base of the tail
  • Forehead a little bit more greyish with a bit of a mask
  • Chest usually with creamy-white markings, sometimes extending to the front legs (can be used for ID-in individuals)
  • Wolverine can move up to 30 km a day.

Observado.org
IUCN species information

If you want to know more about mustelids (weasels, polecats, martens, otters, badgers, etc.), check out the other blog about Mustelids in Europe. Or get some recommended books for more detailed information.

Learn more about Mustelids. This book gives more insights in evolution, diseasis, social communication, and management. Biology and Conservation of Musteloids is part a very good series, with previous topics on Wild Felids and Wild Canids.

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