The plight of the grey wolf and its reintroduction to Yellowstone Park
The grey wolf is a species native in North Africa, Eurasia, and North America. The state of Montana enforced eradication of predators including the grey wolf in 1884 as they were killing other game animals.  The state even offered to pay one dollar for every wolf killed. The wolves were killed by poisoning carcasses and hunting them down. The U.S. Biological Survey was established in 1914, and its main role was to kill off the grey wolf in Yellowstone National Park and its environs. The last wolves in Yellowstone National Park were exterminated in 1926, as they killed buffalos to feed themselves, and by 1927 wolves were almost cleared in Wyoming, Idaho and Montana states.  This led to the imbalance in the ecosystem as population of grazing animals increased leading to eradication of vegetation due to overgrazing.
The Federal Endangered Species Act was passed in 1973, and it protected the grey wolf.  The return of the grey wolf in Yellowstone National park was discussed and accepted in 1995 despite many controversies; thus, 14 wolves were brought to the park from Canada. The 14 wolves brought into the park were released in the Soda Butte Creek, Rose Creek, and Crystal Creek in the Lamar Valley pens. Seventeen more grey wolves were brought into Yellowstone from Canada in 1996 and were released into the Druid Peak, Lone Star, Nez Perce, and Chief Joseph pens Goodenough, 2010. These were believed to multiply and sustain the population of the species in the park. In the year 2005, the number of wolves in Yellowstone national park was recorded to be 235, which showed success in recovery of the grey wolf.