And many people sweating blood and tears to save endemic fishes like the Bonytail, the razorback sucker, the Colorado Pikeminnow, the four Ambystoma species of tiger salamanders, the California Red-legged frog, the Giant and San Francisco Gartersnakes, the California Ridgway's rail. Without talking of the endangered freshwater clams, snails and crustaceans of California.

This man is not a hero. Feral ferrets would treat tens of species of endangered animals of California. They even maybe could block an hypothetical future reintroduction of the American polecat (unlikely, as is a pairie dog specialized hunter from Central US, but not impossible as is one of the most endangered mammals of US).

All this effort could be destroyed for the lack of vision of one single man and the "but is so cute" trap. Nature is too important to be left to the caprices of pet owners.