World Wildlife Fund is the largest private US conservation organization that works worldwide to conserve nature. WWF programs aim to preserve the diversity and abundance of life on Earth and the health of ecological systems by protecting natural areas and wildlife populations, promoting sustainable use of natural resources, and promoting more efficient resource and energy use and the maximum reduction of pollution. WWF is affiliated with the international WWF network, which has national organizations, associates, or representatives in nearly 40 countries. In the United States, WWF has more than 1 million members.