Mustelidae In Alberta

By Shalene Hughes

The word “Mustelidae” is derived from the Latin word Mustela which means weasel.¹ The Mustelidae are a diverse group of carnivorous mammals which includes badgers, minks, otters, wolverines, and – you guessed it – weasels! These mammals usually share the following characteristics: short legs, small skulls, rounded ears, thick fur, and elongated bodies.¹

Short-Tailed Weasel

In Alberta, the most common weasel is the Short-tailed weasel. They are approximately 1 ft in length and weigh approximately 170 g.⁶ Despite their size, they are some of the most carnivorous animals in Alberta, consuming other small mammals, invertebrates, and sometimes amphibians.² Weasels tend to live in thick Albertan vegetation and are most active during the night.² Short-tailed weasels have adapted to the change of the season by changing their colour to blend into their surroundings. During the summer, the weasel is brown with a white belly and during the winter they are mostly white (except for the black tip on their tail) in order to blend into the snow.²

American Badgers

Despite their title, American badgers are also found in parts of Canada, including Alberta. These mammals are 50-80 cm in length and can weigh 13-17 lbs.³ The diet of the American badger consists of small rodents, birds, eggs, reptiles, and large invertebrates³. Grasslands are where these animals use their strong claws to dig elaborate tunnel networks and chambers³. American badgers are grey or brown in colour with white stripes from their face to the middle of their back. Another distinctive feature of an American badger is their fluffy ears which look like earmuffs.

Minks

Minks are usually found in Alberta’s wetlands, although they may stray up to 200 m from the water’s edge in search of food.⁴ A mink’s diet contains mainly of muskrats, but they also consume ducks, amphibians, small mammals, fish, and more⁴ . Minks take up residence in burrows abandoned by muskrats.⁴ When hunting fish, the mink will locate prey from above and plunge into the water as their bodies are not well-equipped for deep diving. Minks have small, slightly webbed feet and fluffy tails.⁴

River Otter

River otters are designed for water dwelling with their flattened tail, webbed feet, thick, insulating pelt, and ability to remain underwater for up to four minutes!⁴ River otters typically eat slow-moving fish species like suckers, minnows, and catfish.⁴ When hunting in conditions where they cannot rely on their eyesight, such as in murky water, river otters rely on their whiskers, which can detect pressure waves that are caused by fish swimming by.⁴

Wolverines

Wolverines are the largest terrestrial Mustelidae.⁵ They are characterized by two stripes along their backs, a thick tail, and a short and stocky frame. Wolverines can range from 16-40 lbs.⁵ The wolverine hunts hares and rodents and scavenges large animals such as moose and caribou.⁵ Territories of the wolverine are vast forested, alpine, and tundra regions that range from 50-1,580 km.² Pregnant wolverines rely on heavily snowed areas in order to dig a den to give birth to their kits and keep them safe while they are growing.⁵

Common Adaptations

Some Mustelidae have unique adaptations; however, they share the following common adaptations. In order to ensure offspring are born during favorable environmental conditions, mustelid reproduction utilizes something called “embryonic diapause.”¹ This means the embryo remains dormant after breeding and the gestation period is extended. This benefits the mustelids as their offspring can be born during months where the weather is less harsh, and food is more accessible.¹ Mustelidae have claws that are suited to the needs of their environment. Some Mustelidae, like the wolverine, have thick claws that allow them to climb trees or tread across rocky cliffs.⁶ Badgers, as previously mentioned, use their large and powerful claws to dig tunnel networks.³ Another adaptation is well-developed anal scent glands. These are key in signaling other Mustelidae for mating or to warn of their territory.⁷ Being carnivorous creatures, Mustelidae require strong and sharp teeth that allow them to consume other mammals, fish, amphibians, and invertebrates.⁷ Mustelidae have many adaptations that allow them to survive the challenging and harsh conditions throughout Alberta.

References

1. iNaturalist. “Mustelids,” n.d. https://www.inaturalist.org/taxa/41770-Mustelidae.  
2. Edmonton & Area Land Trust. “Fun Facts: Alberta’s Adorable Animals,” 2019. https://www.ealt.ca/blog/fun-facts-albertas-adorable-animals.
3. Nature Canada. “American Badger,” n.d. https://naturecanada.ca/discover-nature/endangered-species/american-badger/.
4. Alberta Conservation Association. “Conservation,” Volume 12 (2009): 10-11. https://www.ab-conservation.com/downloads/conservation_magazine/aca_conservationmagazine_v12.pdf.
5. Barney Moss. “Death by ‘Data Deficient’: The disappearance of wolverines in Alberta’s eastern slopes,” (2022). https://naturealberta.ca/death-by-data-deficient-the-disappearance-of-wolverines-in-albertas-eastern-slopes/.
6. Big Lake Environment Support Society. “Animal Guide to Loise Hole Centennial Provincial Park, Alberta,” (2022). https://albertaparks.ca/media/6497327/bless_animal_guide.pdf.
7. Serge Lariviere. “Mustelid,” n.d. https://www.britannica.com/animal/mustelid.