South Florida Ecological Services Field Office
Southeast Region


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Invasive Species

Injurious Wildlife

Large Constrictor Snakes

Burmese python

Burmese python caught at Everglades National Park. Photo credit USGS.

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Current Situation

Service Lists Four Nonnative, Large Constrictor Snakes as Injurious Wildlife

Protections for Native Wildlife and Sensitive U.S. Ecosystems Strengthened Through Prohibitions on Importation and Interstate Transport

March 6, 2015

The U.S. Fish and Wildlife Service (Service) today declared the reticulated python, DeSchauensee’s anaconda, green anaconda and Beni anaconda as “injurious” under the Lacey Act. A fifth snake, the boa constrictor, is removed from consideration for listing as an injurious wildlife species.

The listing will prohibit import of the four snakes into the United States and its territories, as well as transport across state lines for snakes already in the country, and is intended to help restrict the snakes’ spread in the wild. Following opportunities for public comment, an economic analysis and an environmental assessment, the Service produced the final rule, which is expected to publish in the Federal Register March 10. The prohibitions in the rule will go into effect 30 days after publication and apply to live individuals, gametes, viable eggs or hybrids of the four snakes.

“Large constrictor snakes are costing the American public millions of dollars in damage and placing at risk 41 federally and state-listed threatened or endangered species in Florida alone,” said Service Director Dan Ashe during an event to announce the rule at the Arthur R. Marshall Loxahatchee National Wildlife Refuge in Florida. “Today’s action will help prevent humans from contributing to the spread of these snakes.”

In March 2010, the Service proposed listing nine species of large constrictor snakes not native to the United States as injurious wildlife. The listing was finalized in 2012 for four species: Burmese python, yellow anaconda, and northern and southern African pythons. In 2014, the Service reopened the public comment period for the remaining five species, including the boa constrictor. Although the boa constrictor can be damaging to U.S. wildlife, the circumstances surrounding the species, which include widespread private ownership and domestic breeding, render importation and interstate transport prohibitions less effective.

The reticulated python and the green anaconda, considered the two largest snakes in the world, are traded commercially as pets. Some of these powerful snakes have been intentionally released into the wild, while others escape from poorly secured enclosures. Small numbers have been found in the wild in Florida, putting at risk native wildlife unprepared to defend itself against these giant and efficient predators. Prohibiting additional importation and interstate transportation could reduce opportunities for future releases into the wild.

The Beni and DeSchauensee’s anacondas are not known to be in the United States. The Service determined an injurious listing now is the most effective way to prevent future problems like those occurring with the Burmese python. In Florida, Burmese pythons are preying on native wildlife species, including those that are endangered or threatened. Scientists have not found any way of eradicating invasive constrictor snakes once they become established in the wild.

Species are added to the list of injurious wildlife to prevent their introduction or establishment and to protect the health and welfare of humans; the interests of agriculture, horticulture or forestry; and the welfare and survival of wildlife resources.

The Service considered a variety of factors when evaluating these snake species for listing as injurious, such as the species’ survival capabilities and ability to spread geographically, their impacts to threatened and endangered species, and resource managers’ ability to control and eradicate the species.

Most people who own any of these four species will not be affected by this regulation. Those who own any of these species will be allowed to keep them if allowed by state law. However, they will not be allowed transport or sell them across state lines. Those who wish to export these species out of the United States may do so from a designated port within their state after acquiring appropriate permits from the Service.

The final rule, supporting documents and questions and answers about this action are located at the following web site: For more information on the injurious wildlife provisions of the Lacey Act, please read the following fact sheet:

The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. We are both a leader and trusted partner in fish and wildlife conservation, known for our scientific excellence, stewardship of lands and natural resources, dedicated professionals, and commitment to public service.

For more information on our work and the people who make it happen, visit Connect with our Facebook page, follow our tweets, watch our YouTube Channel and download photos from our Flickr page.


Listing the Large Constrictor Snakes as Injurious Wildlife

March 10, 2015 – Final Rule Listing
Listing Three Anaconda Species and One Python Species as Injurious Reptiles

June 24, 2014 – Reopening of Public Comment Period for Proposed Rule
Listing the Reticulated Python, Three Anaconda Species, and the Boa Constrictor as Injurious Reptiles

January 23, 2012 – Final Rule Listing
Action: Listing Three Python Species and One Anaconda Species as Injurious Reptiles

July 1, 2010 – Reopening of Public Comment Period for Proposed Rule
Listing the Boa Constrictor, Four Python Species, and Four Anaconda Species as Injurious Reptiles

March 12, 2010 – Public Comment Period for Proposed Rule
Listing the Boa Constrictor, Four Python Species, and Four Anaconda Species as Injurious Reptiles

January 31, 2008 – Public Comment Period for Notice of Inquiry
Review of Information Concerning Constrictor Snakes From Python, Boa, and Eunectes genera


Miscellaneous Information


Multi-Stakeholder Python Action Workshop - December 10, 2008

A series of three multi-stakeholder workshops have been held to discuss the large constrictor snake threat, develop action items, and share research information/results. Goals for invasive snake management include prevention, eradication, containment, and reduction of snake populations.

Workshop Documents




Report Invasive Species

Did You Know?

  • Florida has more nonnative reptile and amphibian species than anywhere else in the world.
  • More than 80% of the nonnative reptiles and amphibians in Florida arrived here through the pet trade.
  • There are more species of nonnative lizards breeding in Florida than native lizards.
  • Invasive plants and animals cost Floridians more than $500 million each year.
  • Invasive species are the second-leading cause of species endangerment and extinction, after habitat loss.

What Can You Do?

  • Do your research before buying exotic pets, and remember, Don't Let It Loose!
  • Learn to identify invasive nonnative species and report sightings at or 1-888-IVE-Got1 (1-888-483-4681).
  • If you have an exotic pet you can no longer care for, contact the Pet Amnesty hotline at 1-888-IVE-Got1 (1-888-483-4681).
  • Inspect boating and fishing equipment and remove any plants and animals before going home.
  • Learn about laws and regulations regarding nonnative species at

For more information about invasive species in Florida and tips on how you can help, visit

Last updated: May 3, 2019