Least Weasel
Mustela nivalis
Description 5
The smallest carnivores usually burn energy the fastest and have the most active lifestyles, so it is no surprise that the Least Weasel, the miniature among mustelids, consumes roughly half its body weight each day—equal to about two deer mice and a vole. As with other weasels, adult females may be half the size of adult males, and they mature much more rapidly; females are sexually mature at four months, males at eight months. Females produce two litters each year, unlike the larger, slower-breeding Ermine and Long-tailed Weasel. In the north, the fur of the Least Weasel turns from brown to white in winter, camouflaging them in the snow.
Adaptation: Large, shearing carnassial teeth at the back dominate the jaw structure of the Least Weasel, Mustela nivalis, as they do in all members of the weasel family.
Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account
Physical description 6
Least weasels are long and slender, with a long neck, a narrow head, and short limbs. They have large, black eyes and large, round ears. The feet have five fingers with sharp claws. The mass of least weasels varies depending upon their location. In North America least weasels range in weight from 30 to 55 grams, with males being slightly larger than females. Total length ranges from 165 to 205 mm, tail length ranges from 22 to 40 mm. Fur color is chocolate brown on their back and white with brown spots on the underparts. The summer coat is about 1 cm in length. The winter coat, which is about 1.5 cm in length, turns to all white in northern populations and remains brown in southern populations.
Range mass: 30.0 to 55.0 g.
Range length: 165.0 to 205.0 mm.
Other Physical Features: endothermic ; bilateral symmetry
Sexual Dimorphism: male larger
Sources and Credits
- (c) Biopix, some rights reserved (CC BY-NC), http://www.biopix.com/photos/JCS-Mustela-nivalis-62370.JPG
- (c) Cecil Sanders, some rights reserved (CC BY), https://upload.wikimedia.org/wikipedia/commons/7/76/Alaska_Weasel.jpg
- (c) Biopix, some rights reserved (CC BY-NC), http://www.biopix.com/photos/JCS-Mustela-nivalis-62371.JPG
- (c) Biopix, some rights reserved (CC BY-NC), http://www.biopix.com/photos/JCS-Mustela-nivalis-62380.JPG
- (c) Smithsonian Institution, some rights reserved (CC BY), http://eol.org/data_objects/6625130
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065819
