Burmese Pythons as an Invasive Species
The Giant Snakes Could Live in Much of the South
Jul 31, 2008
Florida is well-known for its populations of exotic reptiles. Green iguanas from Central America were released in South Florida, where they found themselves at home in the warm subtropical climate. Spectacled caimans from South America also found the state to their liking. The caimans were imported when American alligators were declared a protected species and could no longer be sold in pet shops.
Both of these reptiles require specific care, and once their owners realized how difficult they are to keep. These animals are restricted to the unique climate of southern Florida, but the latest reptile invader may have just begun its colonization of North America. Burmese pythons, a subspecies of the Indian rock python, are regularly sold as pets in the US, but these snakes, which can reach lengths of over 20 feet, are also often released into the wild. In Florida, the snakes have found the perfect climate, even invading Everglades National Park, where they compete with alligators for food. The problems that these snakes might cause could be much greater than any other introduced reptile, as a risk assessment by the US Geological Survey now suggests.
Where the Burmese Python Can Live
The range of the Burmese python in its native habitat runs from southern China to Indonesia. It is found in more humid climates than other subspecies of Indian rock python and is often thought of as a rainforest species. It does live in the rainforests, but it also makes its home in humid forested regions that are not strictly rainforests. It is perfectly adapted to living in a humid subtropical climate, which is the same climate as the American South. The new risk assessment from the US Geological Survey shows that the snakes can currently live as far north as Central Virginia with potential habitat open as far north as Maryland’s Eastern Shore. Under current conditions the snakes can colonize most of the subtropical South, the wetter regions of the Southwest, and most of California. However, if climate change models are correct, the snakes could extend their range as north as New Jersey and Washington State. See maps at: www.usgs.gov/newsroom/article.asp
Ecological Impact
Where the Burmese python currently lives in Florida, it is a major competitor of the American alligator. American alligators are small prey specialists that live in freshwater wetland environments. The Burmese python is also a small prey specialist, and it prefers to inhabit areas adjacent to wetlands. The two species are eating the same prey and living in the same spots. It is possible that the python will reduce alligator numbers, which were once quite low. The alligator was hunted to near extinction for its hide and for the exotic pet trade. Now, the alligator faces competition with the snakes. Other species that may be affected by the python’s presence include the Key Largo woodrat and the round-tailed muskrat, which the snake is known to eat. If the snake’s range extends northward, it is likely that a host of species are going to be negatively impacted.
Preventing an Ecological Crisis
In order to stop the spread of the pythons, certain policy choices are available. One of these is ban the importation of the pythons, which would stop at least some of the snakes from arriving in pet stores. However, this species is easily propagated in captivity, and captive-bred strains already exist in several color varieties, including albinos. Another idea would be to ban the keeping of these snakes by private owners, which has been enacted in parts of the United States. The problem with this policy is that owners will keep them illegally and, should they decide to get rid of their pets, will be more likely to release the snakes into the wild.
It seems that the Burmese python is now a North American animal, joining such species as feral pigs, pigeons, and monk parakeets as introduced species. The exact ecological consequence of adding such a large predatory snake to the ecosystem is still not clear. However, the potential exists for large numbers of species to be adversely affected with the arrival of this new predator.
