News  Meet the Massachusetts Mustelids

There are few families of wildlife that are as charismatic as the weasel family. Mustelidae, which includes weasels, minks, martens, badgers, wolverines, and otters, is the largest family in Carnivora with over 50 species spread across every continent except Antarctica and Australia. Mustelids can be found in a variety of habitats, including terrestrial and aquatic environments. One thing Mustelids have in common is their ability to mark their territory with a strong, musty smell. Some members of the weasel family, like otters, are famous for their playful personality and bounding gait. 

There are currently 5 species of Mustelids in Massachusetts: fisher, North American river otter, American mink, ermine, and long-tailed weasel. Historically, Massachusetts also had American martens and wolverines but there hasn’t been an established population of either species since the 1800s. Given their similar silhouettes, it can be a challenge to identify which Mustelid you may have spotted. Read the descriptions below to discover the differences between the Massachusetts Mustelids. When you’re ready to test your new knowledge, try identifying the mystery animal in this video!

- What is the approximate size of the animal? An animal can appear larger than it truly is if it’s close to the camera lens! 
- How is the animal moving? Does it have a walking, lumbering, bounding, or trotting gait? 
- What is the shape of the animal’s face, body, and/or tail?
- What type of habitat did you see the animal in?

Appearance:
- Length: 2 – 3 ft., tail is about 1/3 of total body length 
- Weight: 4 – 16 lbs. 
- Rich brown to black fur with grizzled grayish coloring on the head and shoulders, can have white patches of fur on their chest and lower abdomen 
- Long, slender body with short legs and furred tail  
- Pointed face with large, rounded ears set close to the head 
- Sharp, retractable claws that make them well-adapted for climbing trees 

Habitat:
- Upland forests

Diet:
- Small rodents, squirrels, rabbits, birds, eggs, fruit, porcupines, and carrion 

Appearance:
- Length: 3 – 4 ft., tail is about 1/3 of total body length 
- Weight: 11 – 30 lbs.
- Dark brown water-repellent coat, a lighter colored belly, and silver-gray throat 
- Long, slender body with short legs and webbed feet 
- Thick tail that tapers to a point that make them efficient underwater hunters 

Habitat:
- Marshes, lakes, rivers, swamps, and estuaries

Diet:
- Fish, crayfish, snakes, frogs, insects, crustaceans, amphibians, and mammals 

Appearance:
- Length: 1.5 – 2.5 ft., tail is about 1/3 of total body length 
- Weight: 2 – 3 lbs. 
- Dark brown waterproof coat with a white spot on their chin, occasional white markings on the throat, chest, or belly 
- Long, slender body with short legs and partially webbed toes 
- Short, rounded ears and a pointed nose 
- Moderately bushy, near-black tipped tail  

Habitat:
- Lake shores, creeks and streams, swamps, salt and freshwater marshes, and coastlines

Diet:
- Fish, frogs, crustaceans, muskrats, and small mammals

Appearance:
- Length: 6 in. – 1 ft., tail is about 1/3 of total body length 
- Weight: 1.3 – 3.7 oz.  
- Summer coat has brown fur with white underbelly and black tipped tail, winter coat has white fur with black tipped tail  
- Long, slender body with short legs and small rounded ears 
- Will move rapidly in a random pattern or burrow beneath the snow when hunting 

Habitat:
- Deciduous forests, riparian woodlands, stream banks, forest edges, and rocky areas 

Diet:
- Rodents, shrews, rabbits, red squirrels, and insects 

Appearance:
- Length: 1 – 1.5 ft., tail is about 2/3 total body length
- Weight: 3 – 11 oz.
- Summer coat has brown fur with white underbelly and black tipped tail, winter coat has white fur with black tipped tail
- Long, slender body with short legs and small rounded ears 
- Long-tailed weasels are more common than ermines in Massachusetts  

Habitat:
- Woodlands, brushy areas next to fields, and grassy areas alongside wetlands

Diet:
- Rabbits, snowshoe hare, rodents, shrews, moles, and eggs