The Endangered Species Act, which penalizes those who harm plants and animals in danger of extinction, is one way to attempt to save species. But others are being tried around the world.They can be divided into four categories.

First, some countries adopt a conservation reserve policy. The governments set aside large amounts of land for the protection of species and to keep local people out. Second, a "use it or lose it" policy protects species by making them valuable to local people through hunting, harvesting, or other uses; the species remain because they generate income. Third, ecotourism produces income by charging travelers for the opportunity to view wildlife and natural habitats. Fourth, captive breeding works to perpetuate captured species, either for release into the wild or to be sold for a profit.

These strategies can be used...