Long-tailed, Short-tailed, and Least Weasels

There is often confusion about long-tailed, short-tailed, and least weasels. As the habitat post will explain, they are different kinds of weasels. They are different species, in the same genus. I'll go into depth with the scientific classification here:
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Suborder: Caniformia
Family: Mustelidae
Subfamily: Mustelinae
Genus: Mustela
[scientific classification from Wikipedia.com]

Least weasel: mustela nivalis

If you were to think of a weasel, it probably would be a least weasel

-Known as simply 'weasel' in the UK
-Smallest in mustela and carnivora
-Fierce hunters; can kill a large rabbit or many mice quickly
-Size in relation to geography ranges to a great extent

Long-tailed weasel: mustela frenata

Long-tailed weasel with snowshoe hare

-Also known as the bridled weasel or big stoat
-One of the largest mustelids
-Age quickly: weaning process begins at three weeks, and females sexually mature at three or four months
-Lives mostly in the US, but also in parts of Canada and South America

Short-tailed weasel: mustela erminea

Short-tailed weasels are noted for their yellowish underbellies

-Known as the ermine or stoat
-Well-known for its silky white winter coat and rougher brown summer coat
-Collective noun is gang or pack
-Skull is narrower than other weasels

All of these weasels have a conservation status of Least Concern.