Game auctions serve as competitive markets that allow farm and reservation owners to bid on and purchase animals for their facilities. Animals purchased at auctions for these purposes are commonly bought directly as game, or are then bred to supply facilities. Animals used for breeding are generally females, which cost more on average than males due to the increased breeding prospects they present. In addition to sex, other factors that contribute to the prices of animals on auction include the demand for particular species (based on their overall rarity) and the costs of maintaining them. Animals that receive increased interest from poachers, such as rhinos or elephants due to their ivory horns and tusks, present additional risks to game farm operations, and do not typically sell well at auction. However other herbivores, specifically ungulate species, tend to fetch exponentially higher sums than carnivores. Prices for these animals can reach into the hundreds of thousands in South African rands, equivalent to tens of thousands of American dollars. Legal issues and effects Trophy hunting is legal in many countries, through policies that ensure that hunting practices align to a sustainable use of the country's natural resources. Restrictions on the species that can be hunted (e.g., protected species such as brown bears in European Union), are usually based on populations, hunting seasons, number of available licenses and types of arms, calibers and hunting procedures, asuring hunting ethics. Permits and government consent are also required. However, some countries such as Costa Rica, Kenya and Malawi are countries have chosen to ban trophy hunting.. The U.S. Fish and Wildlife Service imposed a ban on imports, limited to elephant trophies from Zimbabwe and Tanzania for 2014–2015. But the ban was lifted and it has currently has granted permits afterwards In 2001, Botswana instituted a one-year ban on lion hunting. They had previously permitted the hunting of fifty lions each year, which caused a shortage in mature males in the population, as the hunters preferred the lions with the largest manes. After the ban, Safari Club International, including prominent member former President George H. W. Bush, successfully lobbied the Botswanan government to reverse the ban. Botswana again banned trophy hunting in 2014, and now villagers claim they get no income from trophy hunters, suffer from damaged crop fields caused by elephants and buffaloes, and African lions killing their livestock. Some conservationists claim trophy hunting is more effective