were introduced to ranches in Texas and Florida for the sake of trophy hunting. These animals are typically hunted on a fee for each kill, with hunters paying $4,000 or more to be able to hunt exotic game. As many of these species are endangered or threatened in their native habitat, the United States' government requires 10% of the hunting fee to be given to conservation efforts in the areas where these animals are indigenous. Hunting of endangered animals in the United States is normally illegal under the Endangered Species Act, but is permitted on these ranches since the rare animals hunted there are not indigenous to the United States. The Humane Society of the United States has criticized these ranches and their hunters with the reasoning that they are still hunting endangered animals even if the animals were raised specifically to be hunted. Game auctions Game auctions have become another source of income destined to preserve wildlife and provide an economic value to their natural habitats. Such is the case of sheep hunting in North America, where large amounts of money are paid at auctions to hunt for them, such as bighorn sheep, dall ram, stone sheep and desert big horn, which constitute the grand slam of trophy sheep hunting. Hunting for sheep has helped to raise funds used to boost populations of these animals while preserving their habitats. Sheep hunt takes place in rugged mountain terrains where spot and stalk is the usual method to hunt for these species, making this hunt a challenge. Only old rams may be taken, and in order to be sure about their age, the sheep hunter has to identify the age and gender by reading the size and shape of their horns that happen to determine the trophy quality. However, the real trophy about this hunt is the whole experience rather than just the animal's head. This type of hunt was probably become so popular thanks to the writings of gun editor and hunter Jack O'Connor. In Africa, game auctions help provide game farms and reserves with their wildlife. These facilities are important in terms of tourism in Africa, one of the continent's largest economic sectors, accounting for almost 5% of South Africa's GDP, for example. South Africa in particular is the main tourist destination on the continent, and as a result, hosts a large number of game auctions, farms, and reservations.