The Collaborative International Dictionary of English v.0.48:

Black-footed ferret \Black"-foot`ed fer"ret\, n.
   a weasellike mammal (Mustela nigripes) inhabiting the
   western North American prairie, having dark feet, a
   dark-tipped tail, and a dark face on a yellowish-brown coat.
   It is an endangered species.
   [PJC] Blackfriar

WordNet (r) 3.0 (2006):

black-footed ferret
    n 1: musteline mammal of prairie regions of United States;
         nearly extinct [syn: black-footed ferret, ferret,
         Mustela nigripes]