DSC_8619 Feral ferret (Mustela putorius furo) male in autumn den. Introduced from Europe in the 1870's, the wild population was augmented again in the 1980's after many commercial ferret-fur farms closed down, and farmers simply released their stock, which has resulted in us having the largest feral ferret population in the world. NZ ferrets are variable in colour, ranging from white through brown to almost black. Darker individuals always have a distinctive brown or black 'bandit' face mark. Otago Peninsula.