The article "Man vs Goat" develops the stages of an animal revolution from animals intended to serve us to pests an nuisances, to killers. The revolution is patient, the animals wait, but then strike quickly. Excerpts from the NY Times article of 10/28/10:
Olympic National Park, Washington
Veteran hiker from nearby Port Angeles, Bob Boardman, ran into an aggressive mountain goat on a popular trail in this park, the scenic centerpiece of a peninsula the size of Massachusetts. The goat pursued the hiker, using its two pointed horns to gore Boardman in the thigh.
In the last minutes of his life, Boardman tried to warn others of the danger, witnesses said.
They licked the bushes for salt from our sweat and urine. They nudged at the packs. They came close to enough to scare us. And when we tried to shoo them, they would not leave.
The Park Service spent years trapping the animals, tranquilizing them with shots fired from helicopters and then airlifting them to the Cascades. But that only spread the problem around.
With every passing year, the goats lost whatever fear they had of man. This was aggravated, of course, by knuckleheads who insist on feeding wild animals, which breaks down barriers.
But all of this was our handiwork. The goats were introduced to give humans something to hunt. A sport. A game. A chase. For almost 100 years, we never feared them. Now, they’ve stopped fearing us, and are even pursuing us.