Its not only the bad reptile owners there are plenty of non native species that are released into the wild. Sparrows, crabs, fish, pigeons, parakeets, rodents..... all of them can push native wild life in to nearly non-existence. Dont forget that most of the ducks,geese and chicken are not native to this continent. It happens every day that they fly off and escape. Its espec. bad when they interbreed with with they native wildlife . Sorry if i rant here a bit but as a responsible snake owner i am a bit tired of hearing the same story over and over again. Btw there are 5 breeds that get over 20ft : anaconda, burmese python, african rock python , reticulated python and i forgot the last(i only have ball python which top out at 6ft)