typically discarded. Some cultures, however, disapprove of such waste. In Nordic countries, hunting for trophies was—and still is—frowned upon. Hunting in North America in the 19th century was done primarily as a way to supplement food supplies, although it is now undertaken mainly for sport. The safari method of hunting was a development of sport hunting that saw elaborate travel in Africa, India and other places in pursuit of trophies. In modern times, trophy hunting persists and is a significant industry in some areas. Conservation tool According to the U.S. Fish and Wildlife Service, hunting "provides an economic incentive" for ranchers to continue to breed those species, and that hunting "reduces the threat of the species' extinction." A scientific study in the journal, Biological Conservation, states that trophy hunting is of "major importance to conservation in Africa by creating economic incentives for conservation over vast areas, including areas which may be unsuitable for alternative wildlife-based land uses such as photographic ecotourism." However, another study states that less than 3% of a trophy hunters' expenditures reach the local level, meaning that the economic incentive and benefit is "minimal, particularly when we consider the vast areas of land that hunting concessions occupy." Financial incentives from trophy hunting effectively more than double the land area that is used for wildlife conservation, relative to what would be conserved relying on national parks alone according to Biological Conservation, although local communities usually derive no more than 18 cents per hectare from trophy hunting. Trophy hunting has been considered essential for providing economic incentives to conserve large carnivores according to research studies in Conservation Biology, Journal of Sustainable Tourism, Wildlife Conservation by Sustainable Use, and Animal Conservation. Studies by the Centre for Responsible Tourism and the IUCN state that ecotourism, which includes more than hunting, is a superior economic incentive, generating twice the revenue per acre and 39 times more permanent employment. At the crosssection of trophy hunting, ecotourism and conservation is green hunting, a trophy hunting alternative where hunters pay to dart animals that need to be tranquilized for conservation projects. The U.S. House Committee on Natural Resources in 2016 concluded that trophy hunting may be contributing to the extinction of certain animals. Animal welfare organizations, including the International Fund for Animal Welfare, claim that trophy hunting is a key factor in the "silent extinction" of giraffes. According to a national survey that the U.S.