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Assessing the Impacts of Pythons in the Greater Everglades: Examination of Diet and Thermal Biology of Python molurus bivittatus

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Frequently anticipated questions:

What does this data set describe?

Assessing the Impacts of Pythons in the Greater Everglades: Examination of Diet and Thermal Biology of Python molurus bivittatus
The Burmese python (Python molurus bivittatus), a native to Southeast Asia, can reach a length greater than twenty feet (Wall 1921, Pope 1961). This python is a long lived (15 - 25 years) behavioral, habitat, and dietary generalist, capable of producing large clutches of eggs (8 - 107) (Lederer 1956, Branch and Erasmus 1984). Observations of Burmese pythons exist in the United States primarily from locations within Everglades National Park (ENP), including; along the Main Park Road in the saline and freshwater glades, and mangroves, between Pay-hay-okee and Flamingo, the greater Long Pine Key area (including Hole-in-the-Donut), and the greater Shark Valley area along the Tamiami Trail (including L-67 Ext.). The non-native species has also been observed repeatedly on the eastern boundary of ENP, along canal levees, in the remote mangrove backcountry, and in Big Cypress National Preserve. From 2002 (when the numbers first began to climb) to 2005, 201 pythons were captured and removed or found dead. In 2006-2007 alone, that number more than doubled to 418. Measured total length for snakes recovered ranged from 0.5 m to 4.5 m including five hatchling-sized animals recovered in the summer of 2004, and two hatchlings captured in 2005. In 2008, 343 pythons were removed, and so far in 2009, 347 individuals have been removed.

The non-native semi-aquatic pythons's diet in southern Florida includes raccoon, rabbit, muskrat, squirrel, opossum, cotton rat, black rat, bobcat, house wren, pied-billed grebe, white ibis, limpkin, alligator and endangered Key Largo wood rat. As Python molurus is known to eat birds, and also known to frequent wading bird colonies in their native range, the proximity of python sightings to the Paurotis Pond and Tamiami West wood stork rookeries is troubling. The potential for pythons to eat Mangrove Fox Squirrels and Cape Sable Seaside Sparrows and to compete with Indigos Snakes is also of concern.

Burmese Pythons present a potential threat to successful ecological restoration of the greater Everglades (NRC 2005). Pythons are now established and breeding in South Florida. Python molurus bivittatus has the potential to occupy the entire footprint of the Comprehensive Everglades Restoration Project (CERP), adversely impacting valued resources across the landscape. Proposed management and control actions must include research strategies and further evaluation of potential impacts of pythons.

The results of this project will be applied to develop a comprehensive, science-based control and containment program. The proposed project will also increase our understanding of the impacts of Burmese pythons on native fauna in DOI and surrounding lands. Dealing with established exotic species requires that we understand their status and impacts, and how to remove them. A current priority item for determining status is finding out the extent of invasion by established species. Once we know where the threat is occurring, we need a better understanding of how the threat may manifest itself ecologically-that is, what are the impacts of invasion? We can hypothesize that Burmese pythons compete with native snakes or affect populations of prey species; however, knowing with certainty that pythons eat wood rats, for example, better focuses eradication efforts and spurs action. A study of diet of Burmese pythons directly addresses this issue. Further, knowing how much pythons eat through a bioenergetic model allows us to forecast with more certainty predation impacts on native fauna.
  1. How should this data set be cited?

    Kristen Hart, Frank J. Mazzotti, Mchael E. Dorcas, Skip Snow, 2010, Assessing the Impacts of Pythons in the Greater Everglades: Examination of Diet and Thermal Biology of Python molurus bivittatus.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -81.5
    East_Bounding_Coordinate: -80.3
    North_Bounding_Coordinate: 29.25
    South_Bounding_Coordinate: 25.1
    Southern Florida, Everglades National Park, Big Cypress National Preserve, Crocodile Lake National Wildlife Refuge, John Pennycamp State Park (Miami-Dade, Monroe, and Collier Counties)

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 2008
    Ending_Date: 2010
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: maps and data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

    2. What coordinate system is used to represent geographic features?

  7. How does the data set describe geographic features?

  8. What biological taxa does this data set concern?

    Taxonomic_Keyword_Thesaurus: None
    Taxonomic_Keywords: reptiles
    Taxon_Rank_Name: Kingdom
    Taxon_Rank_Value: Animalia
    Taxon_Rank_Name: Phylum
    Taxon_Rank_Value: Chordata
    Taxon_Rank_Name: Class
    Taxon_Rank_Value: Reptilia
    Taxon_Rank_Name: Order
    Taxon_Rank_Value: Squamata
    Taxon_Rank_Name: Family
    Taxon_Rank_Value: Pythonidae
    Taxon_Rank_Name: Genus
    Taxon_Rank_Value: Python
    Taxon_Rank_Name: Species
    Taxon_Rank_Value: Python molurus
    Taxon_Rank_Name: Subspecies
    Taxon_Rank_Value: Python molurus bivittatus

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

    • Kristen Hart, Frank J. Mazzotti, Mchael E. Dorcas, Skip Snow

  2. Who also contributed to the data set?

    Mike Rochford, Michael Cherkiss

  3. To whom should users address questions about the data?

    Kristen Hart
    U.S Geological Survey
    Florida Integrated Science Center - Davie Field Office
    Davie, FL 33314

    954-577-6335 (voice)
    954-475-4125 (FAX)

Why was the data set created?

Project objectives:
-Provide science support to evaluate impacts of pythons on native biological diversity. To this end, we will determine the diet of Burmese pythons removed from Everglades National Park in 2008 and 2009.
-To evaluate the impacts of pythons on native biological diversity and development of control measures for Burmese pythons, we must monitor temperature of pythons which serves as a proxy for activity levels.
-Synthesize what is known with the new information provided in above objectives to develop a preliminary conceptual bioenergetic model for Burmese pythons.
-Use resulting data to develop a better understanding of python activity and microhabitat use. Such data will allow better predictions of when animals are exposed and visible, and thus available for capture and removal

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: Unknown (process 1 of 4)
    Task 1: Diet of Burmese pythons:
    We continue to examine the stomach and lower gastro-intestinal tracts of euthanized pythons. Methods involve extracting and washing the stomach and gastro-intestinal tract of each individual python with ethanol, followed by close stereoscopic examination for feathers, hair, teeth, bone fragments, claws and scales. An attempt is made to identify mammal, bird and reptile remains to lowest taxonomic level possible.

    Date: Unknown (process 2 of 4)
    Task 2: Thermal biology of Burmese pythons:
    To record body temperature of free-ranging Burmese pythons, we surgically implant miniature, temperature sensitive data-loggers (micro-dataloggers). We also radiotag each snake to track their movements. Dataloggers are coated with plastic tool dip before implantation into the body cavity, and we program each logger to record temperature every 30 minutes. After a period of time (e.g., one year), we will surgically remove the data-loggers and download the data. We will take simultaneous measurement of environmental temperatures using biophysical snake models (constructed to have the same thermal properties as live snakes) in different thermal environments to allow detailed interpretation of data that can be used for bioenergetic modeling and determination of activity patterns.

    Date: Unknown (process 3 of 4)
    Task 3: Preliminary conceptual bioenergetic model for Burmese pythons:
    To fully evaluate the impacts of pythons on native biological diversity, we must synthesize what is known with the new information provided in Task 1 and Task 2 to develop a preliminary conceptual bioenergetic model for Burmese pythons. While we will know what they are eating from Task 1 (Diet of Burmese pythons) and we will have thermal profiles for tagged pythons Task 2 (Thermal biology of Burmese pythons), we seek to quantify the number and type of each specimen that they may be eating. This type of "impact" has not yet been quantified for this exotic species. We will also use the thermal data in particular to determine when pythons may be more available for removal, i.e., when they may be basking more and out on levees and roads. Such time periods would be ideal targets for python census and removal programs. A new test of python accelerometers also looks promising for determining very fine scale python activity patterns.

    Date: Unknown (process 4 of 4)
    Task 4: Inform removal programs:
    We are synthesizing results of Task 2 (Thermal biology of Burmese pythons) along with radio-tracking results to understand python activity and movement patterns. Temperature affects nearly every aspect of snake biology, and understanding thermal biology allows detailed inferences regarding activity and microhabitat use of pythons providing data. Such data can be used for the development of more effective python control mechanisms. Because we use micro-dataloggers to automatically monitor the body temperatures of free-ranging pythons in Task 2, our resulting data allows us to develop a better understanding of python activity, microhabitat use, and feeding. Such data will allow better predictions of when animals are exposed and visible, and thus available for capture and removal. Thermal data along with very fine scale activity information (derived from a current pilot study with accelerometers) also may indicate when pythons are feeding helping to determine whether it is better to bait or not to bait python traps that may be deployed within the Greater Everglades to protect native resources.

  3. What similar or related data should the user be aware of?

    Branch, W.R. and H. Erasmus, 1984, Captive breeding of pythons in South Africa, including details of an interspecific hybrid (Python sebae natalensis x Python molurus bivittatus): Journal of the Herpetological Association of Africa 30:1-10.

    colvin, B.A., Fall, M.W., Fitzgerald, L.A. and L.L. Loope, 2005, Review of Brown Treesnake problems and control programs: Report of observations and recommendations.

    Other_Citation_Details: Report to Office of Insular Affairs, Honolulu, Hawaii
    Lederer, G., 1996, Fortpflanzungsbiologie und Entwicklung von Python molurus molurus (Linne) und Python molurus bivittatus (Kuhl).: Die Aquarien- Und Terrarien-Zeitschrift 9:243-248.

    Council, National Research, 2005, Re-engineering storage in the Everglades: Risks and Opportunities: National Academies Press, Washington, DC.

    Pope, C.H., 1961, The giant snakes: Alfred A. Knopf, New York.

    Wall, F., 1921, Orphidia Taprobanica or the Snakes of Ceylon: Govt. Printer, Colombo.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?


  5. How consistent are the relationships among the observations, including topology?


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Cite primary authors and database when using or publishing these data

  1. Who distributes the data set? (Distributor 1 of 1)

    Heather S. Henkel
    U.S. Geological Survey
    600 4th Street South
    St. Petersburg, FL 33701

    727-502-8028 (voice)
    727-502-8182 (FAX)
  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    The data have no explicit or implied guarantees.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 29-Sep-2014
Metadata author:
Heather S. Henkel
U.S. Geological Survey
600 4th Street South
St. Petersburg, FL 33701

727-502-8028 (voice)
727-502-8182 (FAX)
Metadata standard:
FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata (FGDC-STD-001.1-1999)

Generated by mp version 2.9.27 on Mon Sep 29 08:06:49 2014

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Last updated: 23 December, 2016 @ 01:49 PM (KP)