Are invasive snakes dangerous?

Free-ranging snakes representing dozens of species from around the world are discovered in the United States in any given year, usually as a result of escapees or releases from the pet trade, but most of these don't appear to have established a reproductive population.

Any animal can be problematic when released in places where it is not native. For example, the brown tree snake was introduced to the American island of Guam shortly after World War II; it has decimated the native birds, mammals and lizards of Guam, such that only a few small species remain. Guam has now lost 10 of its 12 native forest birds, most of its bats, and about half of its native lizards. Burmese pythons introduction to Florida have been linked to severe mammal declines in Everglades National Park.

None of these snakes pose more than minimal risk to human safety. Human fatalities from non-venomous snakes in the wild are very rare, probably only a few per year worldwide.  All known fatalities in the United States are from captive snakes. Predatory attacks by invasive pythons are a possibility, though the rarity of such attacks suggests that they are highly unlikely. 

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Are there invasive reptiles other than Burmese pythons in the United States that people should be concerned about?

Free-ranging snakes representing dozens of species from around the world are discovered in the United States in any given year, usually as a result of escapees or illegal releases, but most of these have not established reproductive populations. Florida is a major transportation hub and has a climate that’s suitable for many invasive species. As a...

Where are Burmese pythons or other large constrictors distributed in Florida?

The Burmese python is now distributed across more than a thousand square miles of southern Florida, including all of Everglades National Park and areas to the north including Big Cypress National Preserve and Collier-Seminole State Forest. A number of Burmese pythons have been found in the Florida Keys, but there is not yet confirmation of a...

How have invasive pythons impacted Florida ecosystems?

Non-native Burmese pythons have established a breeding population in South Florida and are one of the most concerning invasive species in Everglades National Park. Pythons compete with native wildlife for food, which includes mammals, birds, and other reptiles. Severe mammal declines in Everglades National Park have been linked to Burmese pythons...

Can invasive pythons be eradicated?

The odds of eradicating an introduced population of reptiles once it has spread across a large area are very low, pointing to the importance of prevention, early detection and rapid response. And with the Burmese python now distributed across more than a thousand square miles of southern Florida, including all of Everglades National Park and areas...

Could invasive pythons move into cities?

Boa constrictors and northern African pythons live in or adjacent to the Miami metropolitan area, and in their native ranges various python species and the boa constrictor are often found living in suburban and urban areas. As with alligators, the risk of human attack in urban areas is very low but not absent.

Are large constrictor snakes such as Burmese pythons able to kill people? What is the risk?  Would this be in the wild, or in backyards?

Human fatalities from non-venomous snakes are very rare, probably averaging one or two per year worldwide. All known constrictor-snake fatalities in the United States are from captive snakes; these are split between deaths of snake owners who were purposefully interacting with their pet and deaths of small children or infants in homes where a...

What is an invasive species and why are they a problem?

An invasive species is an introduced, nonnative organism (disease, parasite, plant, or animal) that begins to spread or expand its range from the site of its original introduction and that has the potential to cause harm to the environment, the economy, or to human health. A few well-known examples include the unintentional introduction of the...
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Date published: November 1, 2016

Grappling with Pythons in Florida

In 2003, wildlife scientists carrying out regular nighttime road surveys in Everglades National Park started to see fewer medium-sized mammals. Over the next few years, rabbits disappeared completely, and populations of foxes, raccoons, possums, bobcats, and white-tailed deer were either small or absent.

Date published: September 22, 2016

Burmese Python Hatchlings Seen on Key Largo

Burmese pythons have been found on Key Largo.

Date published: March 3, 2016

Brown Treesnake Rapid Response Team Deployed to Saipan after Two Snake Sightings

Two recent reports of two brown treesnakes on Saipan is prompting federal and state officials to urge citizens of Hawaii, Guam and other Pacific Islands to report any sightings of these invasive snakes to authorities. Snakes can be reported by calling (671) 777-HISS or (670) 28-SNAKE.

Date published: April 28, 2015

Burmese Python Habitat Use Patterns May Help Control Efforts

EVERGLADES NATIONAL PARK, Fla.— The largest and longest Burmese Python tracking study of its kind -- here or in its native range -- is providing researchers and resource managers new information that may help target control efforts of this invasive snake, according to a new study led by the U.S. Geological Survey.

Date published: February 27, 2014

Burmese Pythons Pose Little Risk to People in Everglades

The estimated tens of thousands of Burmese pythons now populating the Everglades present a low risk to people in the park, according to a new assessment byU.S. Geological Survey and National Park Service scientists.

Attribution: Ecosystems, Southeast
Date published: November 29, 2012

Invasive Boa Constrictor Thriving on Puerto Rico

MAYAGÜEZ, Puerto Rico— Non-native boa constrictors, which can exceed 10 feet and 75 pounds, have established a breeding population in Puerto Rico, one that appears to be spreading, according to research published in the journal Biological Invasions.
 

Date published: January 30, 2012

Severe Declines in Everglades Mammals Linked to Pythons

HOMESTEAD, Fla. -- Precipitous declines in formerly common mammals in Everglades National Park have been linked to the presence of invasive Burmese pythons, according to a study published today in the Proceedings of the National Academy of Sciences. 

Date published: February 9, 2011

Challenges identified in using models to predict snake and other animal invasions

New research published today has identified challenges in using computer models to predict the potential of pythons or other invasive vertebrate species to spread across portions of the United States, according to the U.S. Geological Survey.

Date published: October 13, 2009

Report Documents the Risks of Giant Invasive Snakes in the U.S.

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 released today.
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.

Date published: March 22, 1999

Controlling Problem Snakes: Saipan Benefits From USGS Research

The newly released book "Problem Snake Management: The Habu and the Brown Treesnake" promises to be instrumental in helping Saipan and other Pacific Islands confront the threat of brown tree snakes, a prolific pest species that has caused health and economic hazards for Guam’s residents, as well as devastating native bird, lizard, and bat populations.

Date published: November 7, 1997

Snake Barrier On Rota is Important Step Toward Preventing Future Spread of Brown Tree Snake

A new way to prevent brown tree snakes from invading was unveiled yesterday by scientists working for the U.S. Department of the Interior’s U.S. Geological Survey and Ohio State University.

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American Alligator and Burmese Python in a Struggle
February 1, 2017

American Alligator and Burmese Python in a Struggle

An American alligator and a Burmese python locked in a struggle to prevail in Everglades National Park. This python appears to be losing, but snakes in similar situations have apparently escaped unharmed, and in other situations pythons have eaten alligators. Photograph credit: Lori Oberhofer, National Park Service

An Everglades Park ranger holds a Burmese Python by the tail.
October 4, 2016

An Everglades Park ranger holds a Burmese Python by the tail.

An Everglades Park ranger holds a Burmese Python by the tail. 

video thumbnail: Under Siege: Battling Flying Carp and Giant Pythons and How Science Can Help
July 3, 2012

Under Siege: Battling Flying Carp and Giant Pythons and How Science Can Help

Over the last several decades, non-native species have continued to invade sensitive ecosystems in the United States. Two high-profile species, Asian carp in the Midwest and Burmese pythons in the Everglades, are the focus of much attention by decision makers, the public and the media. Sharon Gross, Robert Reed and Cynthia Kolar discuss issues related to invasive species

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Image: Biologists Remove Python from Everglades
May 1, 2012

Biologists Remove Python from Everglades

This 16 1/2-foot python, being removed from the wild by USGS and NPS personnel, was captured in a thicket in Everglades National Park in May 2012. The python was equipped with a radio-transmitter and an accelerometer as part of one of the Burmese python projects led by USGS to learn more about the biology of the species to help in efforts to develop better control methods

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video thumbnail: Record-Breaking Burmese Python (17 feet, 7 inches, 87 eggs) Captured by The USGS, B-roll
March 31, 2012

Record-Breaking Burmese Python (17 feet, 7 inches, 87 eggs) Captured by The USGS, B-roll

Big Ol‘ Gal

This female Burmese python broke the records for her length — 17 feet, 7 inches — and the number of eggs she contained: 87. She was first captured in Everglades National Park by USGS researchers in the spring of 2012, when they followed a "Judas snake" – a male python with a transmitter – and found her nearby in the bushes. USGS scientists then

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