Weasels belong to the genus Mustela in the subfamily Mustelinae. This subfamily also houses martens, wolverines and other close relatives in addition to weasels. Other members of the genus Mustela include mink, ermines and ferrets, all of which are closely related to the weasels and sometimes even commonly referred to as such. Weasels rarely stray from a strictly carnivorous diet, although some species will occasionally take fruits and other plants.
As carnivores, weasels prefer to hunt down a wide range of prey, although rodents make up the largest part of the diet for almost all weasel species. In some species, such as the long-tailed weasel, the females are more apt to capture small rodents because their smaller body size allows them to easily gain entrance to the burrows of unsuspecting prey. Moles, voles and mice are in high demand for the voracious appetites of weasels.
It isn't uncommon to spot a long-tailed weasel feasting on a freshly killed cottontail rabbit or similar creature, despite the generous size difference between predator and prey. Males are more adaptable to larger game, just as females of many species are more adaptable to hunting smaller game. In the case of the least weasel (Mustela nivalis), males are better hunters in general and capable of hunting larger game.
Many weasels rely largely on insects and other invertebrates, as well as reptiles and amphibians, as a large part of their diet, particularly when rodents and other food sources are scarce. Snakes, lizards, frogs and arthropods are all on the menu when it comes to these slender-bodied predators.
Birds may be the second-most preferred food source after mammals. Long-tailed weasels have been known to kill an entire coop of chickens and seem to prefer poultry, according to Northern State University. Some weasels will even venture into trees to capture unsuspecting birds and their nests full of freshly laid eggs.
- University of Michigan Animal Diversity Web: Mustela Altaica
- University of Michigan Animal Diversity Web: Mustela Frenata
- University of Michigan Animal Diversity Web: Mustela Kathiah
- University of Michigan Animal Diversity Web: Mustela Nivalis
- Northern State University: Long-Tailed Weasel
- University of Michigan Animal Diversity Web: Genus Mustela Classification
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