If we were to reintroduce large predators (such as grizzly bears, timber wolves, jaguars, cougars, alligators, and crocodiles) to urban areas, we would curb population growth naturally. In accordance with Darwinist theory, only the strong will survive being picked off, and in accordance with so-called environmentalist ethics, these beautiful animals would be saved from extinction.
In the 1700s, as the population of Europe rose, there were numerous packs of man-eating wolves that stalked the outskirts of cities such as Paris. Wolf populations thrived, and the population of France was curbed.
The reintroduction of Darwinian forces will bring us back into balance with the world. Large predatory species will be saved from extinction, and only the strong (and smart) will survive.