 Walter Meshaka, senior curator for the State Museum of Pennsylvania, stated that pythons are very good swimmers and, therefore, it seemed reasonable to assume it had swum from the Everglades into the Key Largo area refuge.From 2008 to 2013, a USGS study focused on detection and removal of pythons on the refuge yielded very few snakes.Feral and free-ranging cats have been identified as a major factor in the significant decline of the Key Largo woodrat and the Key Largo cotton mouse.