A long-awaited federal report on Burmese pythons and other giant non-native snakes could give a boost to pending legislation that would ban their importation.

The 300-page report, issued in October by the U.S. Geological Survey, concludes that nine boa, anaconda and python species are invasive or potentially invasive and represent a medium to high ecological risk.

“This report clearly reveals that these giant snakes threaten to destabilize some of our most precious ecosystems and parks, primarily through predation on vulnerable native species,” said Dr. Robert Reed, a co-author of the report and a USGS invasive species scientist and herpetologist.

The authors emphasized that native U.S. birds, mammals and reptiles in areas of potential invasion have never had to deal with huge predatory snakes before.

Based on the biology and known natural history of the giant constrictors, mature individuals of the largest species—Burmese pythons, reticulated pythons, and northern and southern African pythons—also may pose a small risk to people, the report also found.

Breeding populations of wild Burmese pythons and boa constrictors have been confirmed in South Florida, and there is strong evidence that the northern African python may have a breeding population in the wild as well, according to the report.

The report further notes that there are no control tools yet that seem adequate for eradicating an established population of giant snakes once they have spread over a large area.

The Pet Industry Joint Advisory Council (Washington) is preparing a formal response to the USGS report, according to Dr. Jamie Reaser, vice president of environmental policy and communications. “There is quite a bit of ground to cover—it has issues from scientific, economic and policy perspectives. Many of the problems are the same problems that were in the previous USGS paper on climate matching.”

Like the 2008 USGS climate-matching study to which Reaser referred, the new report regards the Indian python and Burmese pythons as the same species. However, many scientists view them as separate species, which could change results and conclusions, according to Reaser.

Pending legislation—Senate Bill 373 and House Resolution 3811—introduced in Congress this summer originally sought a ban on the importation of all species of pythons. After successful lobbying efforts by PIJAC and others, the House bill was amended in committee to narrow the ban to Burmese pythons and African rock pythons.

But the Humane Society of the United States (Washington) was quick to point to the USGS report as evidence that a ban on all large constricting snakes is needed. “The 300-page study should ease any doubts about whether these giant creatures belong in the pet trade,” blogged Wayne Pacelle, president of HSUS. “If only some species are restricted, the trade could shift to other large constrictors, and the problem will be moved rather than solved.”

Meanwhile, the U.S. Fish and Wildlife Service will include the new USGS study with other data it has collected in deciding early next year whether to list any snakes in the python, boa and eunectes genera as injurious under the Lacey Act. It is illegal to import, export or trade injurious species in interstate commerce. A final ruling wouldn’t come until 2011, however, after the public has had time to comment on the proposed ruling and the FWS reviews the comments.

HSUS and other supporters of a comprehensive ban on large constricting snakes are pushing for faster action through the pending federal legislation. Both bills remained in committee at press time. [December 2009 PET AGE]