"While some animals get off comparatively easily in the winter by hibernating, or by gorging and then fasting, the short-tailed weasel has to hunt every day to keep its blast-furnace metabolism stoked. With a heart rate of several hundred beats a minute and little in the way of fat reserves on its long and slender body, the animal must consume half its body weight daily.
The same metabolism that keeps the weasel in an almost-constant state of hunger also makes it a quick, effective hunter. Aided by its keen sense of smell, the short-tailed weasel is capable of climbing trees, swimming rivers, diving into small rodent holes in the ground and hunting by day or by night in its search for prey. Its tastes are versatile, ranging from earthworms to waterfowl, although mice are its most common prey. In days of plenty, the energetic short-tailed weasel may kill more than it needs, and stockpile the carcasses for leaner days ahead."