Historical, current, and potential population size estimates of invasive wild pigs (Sus scrofa) in the United States

  • Jesse S. LewisEmail author
  • Joseph L. Corn
  • John J. Mayer
  • Thomas R. Jordan
  • Matthew L. Farnsworth
  • Christopher L. Burdett
  • Kurt C. VerCauteren
  • Steven J. Sweeney
  • Ryan S. Miller
Original Paper


To control invasive species and prioritize limited resources, managers need information about population size to evaluate the current state of the problem, the trend in population growth through time, and to understand the potential magnitude of the problem in the absence of management actions. This information is critical for informing management actions and allocating resources. We used two national-scale data sets to estimate historical, current, and future potential population size of invasive wild pigs (Sus scrofa; hereafter wild pigs) in the United States. Between 1982 to present, the Southeastern Cooperative Wildlife Disease Study mapped the distribution of wild pigs in the United States. In addition, recent research has predicted potential population density of wild pigs across the United States by evaluating broad-scale landscape characteristics. We intersected these two data sets to estimate the population size of wild pigs in 1982, 1988, 2004, 2010, 2013, and 2016. In addition, we estimated potential population size if wild pigs were present at equilibrium conditions in all available habitat in each state. We demonstrate which states have experienced recent population growth of wild pigs and are predicted to experience the greatest population increase in the future without sufficient management actions and policy implementation. Regions in the western, northern, and northeastern United States contain no or few wild pig populations, but could potentially support large numbers of these animals if their populations become established. This information is useful in identifying regions at greatest risk if wild pigs become established, which can assist in prioritizing management actions aimed at controlling or eliminating this invasive species across broad to local scales.


Feral swine Invasive species Introduced species Population size Range expansion 



This study was funded and supported by the Wildlife Services/National Wildlife Research Center and Veterinary Services/Center for Epidemiology and Animal Health programs of the US Department of Agriculture/Animal and Plant Health Inspection Service, the National Feral Swine Damage Management Program, Colorado State University, Conservation Science Partners, and Arizona State University. Funding for preparation of the SCWDS distribution maps and development and maintenance of the NFSMS was through Cooperative Agreements with the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services. Support for this study was provided by the Department of Energy to the Savannah River National Laboratory under contract DE-AC09-08SR22470. J. Anderson assisted with calculation of prediction intervals. We thank B. Dickson and reviewers for providing thoughtful feedback that improved earlier versions of this paper.

Supplementary material

10530_2019_1983_MOESM1_ESM.docx (370 kb)
Supplementary material 1 (DOCX 370 kb)


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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Jesse S. Lewis
    • 1
    • 8
    Email author
  • Joseph L. Corn
    • 2
  • John J. Mayer
    • 3
  • Thomas R. Jordan
    • 4
  • Matthew L. Farnsworth
    • 1
  • Christopher L. Burdett
    • 5
  • Kurt C. VerCauteren
    • 6
  • Steven J. Sweeney
    • 7
  • Ryan S. Miller
    • 7
  1. 1.Conservation Science PartnersFort CollinsUSA
  2. 2.Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary MedicineUniversity of GeorgiaAthensUSA
  3. 3.Savannah River National LaboratorySavannah River Nuclear Solutions, LLCAikenUSA
  4. 4.Center for Geospatial Research, Department of GeographyUniversity of GeorgiaAthensUSA
  5. 5.Department of BiologyColorado State UniversityFort CollinsUSA
  6. 6.USDA/APHIS/Wildlife ServicesNational Wildlife Research CenterFort CollinsUSA
  7. 7.United States Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary ServicesCenter for Epidemiology and Animal HealthFort CollinsUSA
  8. 8.College of Integrative Sciences and ArtsArizona State UniversityMesaUSA

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