The long-tailed weasel resembles the ermine but has a longer tail, 9.5-16 cm (3.6-6.3 in) in length and greater than 44 percent of the head-body length. This is the only other member of the weasel ...

This 2-foot-long, black-masked member of the weasel family once occurred in central grasslands and basins from southern Canada to Texas but is now one of the most endangered mammals in North America.