Below are comparison photos of other types of weasels found in the United States.
Notice the physical differences between these guys and the domesticated ferret...
Short-tailed weasel with summer coat. Note the bi-colored fur, brown on top and white on bottom. In the summer, Ermine, long-tailed weasels, and least weasels also have this coloration. They tend to turn lighter or white for the winter.
Ermine with winter coat. Note the black tail tip.
Mink. Note how coloration, body shape, and facial features differ from domesticated ferrets. And yes, this guy is obviously quite wet. Mink often love water and eat fish and waterfowl, as well as other prey.
Black-footed ferret. These guys are very rare and extremely endangered. They are being re-introduced to native habitat in the Dakotas and Wyoming. Note the elongated neck in comparison with the domesticated ferret, as well as the very dark and pronounced mask.