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Black-footed Ferret

April 19, 2021
Nicole Doll
Black-footed ferrets
  • Scientific NameMustela nigripes 
  • SARA Status: Extirpated
  • COSEWIC Status: Extirpated – The ferret no longer occurs wild in Canada.  
  • COSEWIC Range: Alberta, Saskatchewan 

The Black-footed ferret was announced extirpated from Canada in 1978, then re-examined and confirmed in 2000. 

Photo by Kimberly Fraser/ USFWS 

The black-footed ferret is the only ferret species native to North America. They are endearing little creatures, weighing only 0.75 to 1.2 kilograms and growing to about 0.5 meters long. While they are now extirpated from Canada, their former range occupied southeastern Alberta and southwestern Saskatchewan. The last known ferret was found in Saskatchewan in 1937.  

The black-footed ferret is an obligate carnivore, meaning it relies on a specific prey item for food. Although they have been observed to consume other small rodents and birds, the prairie dog is responsible for over 90% of their diet.  

The black-footed ferret is nocturnal and hunts during the night while the prairie dogs are sleeping. Their slender bodies allow them to squeeze through the burrows dug by the prairie dogs and to surprise attack them while they are sleeping and least expect it. Not only do black-footed ferrets rely on prairie dogs for food, but they also utilize their burrows for habitat, a refuge from predators and extreme weather, and also storage of prey.  

When the prairie dog population diminished due to control measures and diseases such as the sylvatic plague, the tightly linked association caused the black-footed ferret to become extremely vulnerable.  At one time, black-footed ferrets were considered to be globally extinct until a farmer’s dog had captured one in Wyoming in 1981.

Researchers went out and discovered a colony of them, which they captured in an attempt to breed captive in order to save the species. However, they were only successful in breeding seven of them. Somehow, those seven ferrets were genetically diverse enough to create a population. Today, all living black-footed ferrets are descendants of the seven ferrets that were found in Wyoming.  

Threats: Aside from being totally dependent on prairie dogs, other factors that have influenced the decline of the species are diseases such as rabies and the sylvatic plague, and predators.  Furthermore, with such limited genetic diversity, black-footed ferrets are more susceptible to extreme weather events caused by climate change.  

What’s being done: There has been a number of reintroduction efforts of the black-footed ferret, all of which are bred from the Wyoming population. Researchers predict that prairie colonies must cover at least 4,000 hectares of land in order to support a black-footed ferret population. 

Since the remaining grasslands in Canada are so fragmented by agriculture, Grasslands National Park was one of the only viable options for a reintroduction site in the Canadian Prairies since it contains a large area of protected prairie. In 2009, 74 ferrets from the Toronto zoo were released into Grassland National Park. However, there has not been total success, as threats such as droughts and non-native diseases wiped out populations. There hasn’t been one spotted since 2014.  

There have been 19 other reintroduction programs across North America that have slightly increased the hope of survival of the species. A big improvement considering that they were once thought to be globally extinct. Today, there is thought to be around 1000 living in the wild. It is hoped that the black-footed ferret can once again become part of the prairie ecosystem.