The Least Weasel: Illinois' Smallest Carnivore

Updated: Dec 22, 2020

Illinois is home of two weasel species, the long-tailed weasel and the least weasel. Both have long, slender bodies with short legs and tails, and they are covered in brown and white fur. However, the long-tailed weasel is at least double the size of the least weasel. This cute predator is the smallest carnivore in Illinois, measuring up to 10 inches in length. That’s shorter than a ruler!

The least weasel is the smallest carnivore in Illinois. (Photo via Shutterstock)

Home sweet home


Least weasels can be found in the northern half of Illinois. They prefer open areas like meadows, prairies and farm fields. They live in dens created from rock or brush piles as well as burrows dug by mice, moles or chipmunks.


Weasels can make their homes cozy by lining their nests with grass, fur or feathers from their prey. The key to a happy least weasel home is a high rodent population. If prey is abundant, a weasel only has to live in a 1-acre to 2-acre area. However, that home range can be as large as 65 acres if rodents are few and far between.


The hunt


Seeing a least weasel can be tricky. Although they can be seen during the day, most of their activity happens at night. Plus, their slender bodies are built to hunt in underground tunnels. Their main foods are mice and voles, but eggs, young birds and insects can also make appearances on the menu.


Weasels must stay active and keep eating. They have a high metabolic rate, and their heart beats up to 400 beats per minute! Compare that to humans. Adults typically have a heart rate of between 60 beats to 100 beats per minute. Weasels eat a lot too. They must eat a third or more of their body weight every day!

Least weasels eat rodents like mice and voles as well as eggs, birds and insects. (Photo via Shutterstock)

Weasels kill smaller prey with a few quick bites to the back of the neck. Because least weasels are carnivores, they have sharp canine teeth perfect for the job. They sometimes will stalk bigger prey, hoping to catch them by surprise. The weasel will jump on the animal with its front and hind feet and wrestle it until it is in the correct position for a powerful bite.


This description may ring a bell if you remember the viral photograph from a few years ago of a weasel riding on the back of a woodpecker. It was captured in London, England, by an amateur photographer. Check it out:


Fashionable and protective winter coats


Although the least weasel is fierce predator, it is still smaller than the rest of the carnivores in the wild. Owls, hawks, foxes and others can take down the least weasel.


To help it outsmart its predators, weasels grow a special fur coat. During the summer months, they have reddish-brown backs with white bellies and chests, matching nicely with the soil and other vegetation. Come winter, that coloring would stick out against the snow. Therefore, least weasels grow a new coat, becoming white to blend in with their surroundings.

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