In the 19th century, as the settlers began increasingly moving west in pursuit of more land for ranching, wolves were becoming increasingly more hunted as threats to livestock. In 1818, a "War of Extermination" against wolves and bears was declared in Ohio. Iowa began its own wolf bounty in 1858, with Wisconsin and Colorado following suit in 1865 and 1869. Wolf pelts soon began to increase in demand as beavers began to become scarce from over-trapping. In the 1830s, a wolf pelt was worth only $1, doubling in the 1850s. Records of the upper Missouri outfit of the American Fur Trading Company indicate that 20 wolf pelts were shipped down-river in 1850, with 3,000 being shipped three years later. Civilians turned Bounty hunters known as "Wolfers" began killing ungulates in large numbers as bait, poisoning the meat in hopes of attracting unsuspecting wolves. It is estimated that by the 1870s, this method was killing 100,000 wolves annually.