The Small Weasels
Last Review/Updated: May 31, 2002
Mustela spp.
The small weasels are some of our most beneficial predators, eating mice and other rodents that can cause problems to agriculture. The least weasel, on the left in the color illustration, is the smallest living carnivore. It is found in all life zones in Alberta. Its small size enables it to readily capture moles, mice and shrews. It also eat insects. In winter, least weasels are completely white. They may give birth to three to five young during any month of the year.
The other two weasels in the color illustration are short-tailed weasels or ermine. They are shown in both summer (brown) and winter (white) pelage. Its smaller size, white feet and northern distribution distinguishes this species from the long-tailed weasel (not shown in the color illustration). Mating usually occurs in July or August and four to eight young usually arrive in April or May.
The long-tailed weasel (see below) inhabits the southern parkland and prairie zones. Although its range includes the United States and Mexico, only northern populations turn white in winter. Mating usually occurs in August and four to eight young are usually born in late April.
Least Weasel
Mustela rixosa
- 20 cm (8 in.) long; 70 g (2.5 oz.) in weight — short tail without black tip — white feet
Short-tailed Weasel (Ermine)
Mustela erminea
- 33 cm (13 in.) long; 170 g (6 oz.) in weight — black tip on tail — white feet
Long-tailed Weasel
Mustela frenata
- 45 cm (16 in.) long; 340 g (12 oz.) in weight — black tip on tail — brown feet
