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. Learn more about the Mustela nivalis, more commonly known as a Least Weasel, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.