October 14, 2009
--The world's heaviest snake, the green anaconda
is one of nine huge alien snake species that may wreak havoc if they take hold in the United States, according to a U.S. Geological Survey (USGS) report released this week. (Read full story: "Alien Giant Snakes Threaten to Invade Up to 1/3 of U.S."
The giant snake (pictured in the Peruvian Amazon) can reach lengths of 23 feet (7 meters) and weigh in at 550 pounds (227 kilograms). The olive-green reptiles would flourish in the Florida
Peninsula and in southern Texas
, regions that have climates similar to the anaconda's native South American habitat, the study authors say.
USGS scientists rated the nine snakes based on the risk of the reptiles becoming established in the U.S., which is most likely to happen in areas where pet snakes are commonly released into the wild. The green anaconda is among four species considered medium risks--the species is not popular as a pet, and fewer than 500 of the animals arrive in the U.S. each year from South America, according to the report. Though green anacondas have been found in the wild in Florida, there is no evidence they are breeding.
The five in the following gallery are the true giants, but the USGS scientists also studied four "look alike" species: the southern African python, DeSchauensee's anaconda, the Beni anaconda, and the yellow anaconda.
, senior herpetologist at the Florida Museum of Natural History in Gainesville, called the report "extremely thorough." But it came as "no real surprise that giant constrictors can potentially be a threat to not only the wildlife here but to the humans," added Krysko, who was not involved in the report.
Green anacondas have not been known to attack humans, but their tastes vary widely, including fish, turtles, dogs, and tapirs. The snakes ambush prey from the water and constrict them with an immediately deadly, bone-crushing force. (Watch an anaconda hunt the world's largest rodent
Photograph by Ingo Arndt, Minden Pictures, National Geographic Image Collection