Burmese pythons that were once pets have been released into the Florida Everglades and have established large populations that threaten the ecosystem. They prey heavily on native mammals and birds. In 2013, Florida began holding python challenges where hunters are paid to remove pythons from the Everglades in order to control the invasive snake population. Over 1,600 hunters from several states and countries participated in the first challenge, removing 68 pythons. Ongoing challenges and efforts aim to limit the pythons' negative impacts on local wildlife.