World Wildlife Fund worlwildlifefoundation.org black-footed ferret Mustela nigripes World Wildlife Fund Mustela nigripes Mustela nigripes Mustela nigripes Mustela nigripes Black-footed Ferret 1 World Wildlife Fund black-footed ferrets World Wildlife Fund highly endangered. Mustela nigripes most endangered Black-footed Ferret http://www.worldwildlife.org/species/black-footed-ferret (source) Mustela nigripes Black-footed ferrets black-footed ferret black-footed ferret Mustela nigripes http://www.worldwildlife.org/species/black-footed-ferret