Five giant non-native snake species would pose high risks to the health of ecosystems in the United States should they become established here, according to a U.S. Geological Survey (USGS) report.

The USGS report details the risks of nine non-native boa, anaconda and python species that are invasive or potentially invasive in the United States.

Based on the biology and known natural history of the giant constrictors, individuals of some species may also pose a small risk to people, although most snakes would not be large enough to consider a person as suitable prey.

Mature individuals of the largest species-Burmese, reticulated, and northern and southern African pythons-have been documented as attacking and killing people in the wild in their native range, though such unprovoked attacks appear to be quite rare, the report authors wrote.

The snake most associated with unprovoked human fatalities in the wild is the reticulated python. The situation with human risk is similar to that experienced with alligators: attacks in the wild are improbable but possible.

“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 coauthor of the report and a USGS invasive species scientist and herpetologist.

High-risk species-Burmese pythons, northern and southern African pythons, boa constrictors and yellow anacondas-put larger portions of the U.S. mainland at risk, constitute a greater ecological threat, or are more common in trade and commerce. Medium-risk species-reticulated python, Deschauensee’s anaconda, green anaconda and Beni anaconda-constitute lesser threats in these areas, but still are potentially serious threats.

The USGS scientists who authored the report emphasized that native U.S. birds, mammals, and reptiles in areas of potential invasion have never had to deal with huge predatory snakes before-individuals of the largest three species reach lengths of more than 20 feet and upwards of 200 pounds.

The reticulated python is the world’s longest snake, and the green anaconda is the heaviest snake. Both species have been found in the wild in South Florida, although breeding populations are not yet confirmed for either.

"Researchers implant a radio transmitter in a 16-foot, 155-pound female Burmese python (Python molurus) at the South Florida Research Center, Everglades National Park. Radio-tracking builds understanding of where pythons spend their time and therefore where they can be controlled in practice. Photo courtesy of Lori Oberhofer, National Park Service. (Credit: U.S. Geological Survey)"

Source: United States Geological Survey