Thanks to its camouflage abilities and its speed and agility, the least weasel is rarely caught. The diet of the least weasel is made up primarily of voles and mice, which, because of the weasels' high metabolism, they hunt constantly. One family of these little weasels can consume thousands of rodents each year, making them important in controlling pest populations. Because it is so small, the least weasel can follow mice into their burrows and eat them there. Like other weasels, they will occasionally then make their victim's home their own, lining it with the fur of the former resident when preparing to nest.
Least weasels can produce two litters a year, with three to five young per litter.