Florida's python problem first came to national attention four years ago when a 13-foot Burmese pyton tried to swallow a 6-foot alligator in Everglades National Park - and exploded (see AP photo above).

The U.S. Fish and Wildlife Service will soon decide whether to list the python as an "injurious species," which would result in a ban on imports and interstate trade. U.S. Sen. Bill Nelson, D-Florida, introduced a bill to impose the bans immediately.

"We've spent billions restoring the Everglades ecosystem," Nelson said in a statement issued Thursday by his office. "Yet the place is infested with abandoned pet pythons that have no natural predators and are killing protected species there."