The most critically endangered of any animal in the Everglades region is the Florida panther (Puma concolor coryi), a species that once lived throughout the southeastern United States: there were only 25–30 in the wild in 1995. The panther is most threatened by urban encroachment, because males require approximately 200 square miles (520 km2) for breeding territory. A male and two to five females may live within that range. When habitat is lost, panthers will fight over territory. After vehicle collisions, the second most frequent cause of death for panthers is intra-species aggression.[46] In the 1990s urban expansion crowded panthers from southwestern Florida as Naples and Ft. Myers began to expand into the western Everglades and Big Cypress Swamp. Agencies such as the Army Corps of Engineers and the U.S. Fish and Wildlife Service were responsible for maintaining the Clean Water Act and the Endangered Species Act, yet still approved 99% of all permits to build in wetlands and panther territory.[47] A limited genetic pool is also a danger. Biologists introduced eight female Texas cougars (Puma concolor) in 1995 to diversify genes, and there are between 80 and 120 panthers in the wild as of 2008.[46]