Baseline physiologic and hematologic health in wild-caught muskrats (Ondatra zibethicus) from a near-pristine ecosystem in northern Minnesota

Olivia Aarrestad, Benjamin R. Matykiewicz, Steve K. Windels, Adam A. Ahlers, Bryce T. Olson, Aaron Rendahl, Erin N. Burton, Tiffany M. Wolf

Research output: Contribution to journalArticlepeer-review


Muskrat (Ondatra zibethicus) populations show long-term and widespread declines across North America, necessitating research into potential mechanistic explanations, including population health. Previous research established reference hematology values, a proxy of individual health, of muskrats occurring in highly modified ecosystems. However, our knowledge of hematology metrics in muskrat populations occurring in more natural ecosystems is limited. We measured several hematological parameters of wild-caught muskrats (n ¼ 73) in the Greater Voyageurs Ecosystem in northern Minnesota in 2018-2019 to establish baseline muskrat health in a relatively intact, near-pristine ecosystem. Additionally, we measured rectal temperature and heart and respiratory rates and collected whole blood for complete blood cell count assessment. We established baseline physiologic and hematologic reference ranges for the population and describe variations between total white blood cells, nucleated cell differentials, and basic erythron and platelet estimates and demonstrate methods of estimation to be poor proxies for more standardized counting methods. Our results establish a baseline to compare muskrat health assessments for populations affected by landscape change or in decline.

Original languageEnglish (US)
Pages (from-to)698-703
Number of pages6
JournalJournal of Zoo and Wildlife Medicine
Issue number2
StatePublished - Jun 11 2021

Bibliographical note

Funding Information:
Acknowledgments: Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (project M.L. 2018, Chp. 214, Art. 4, Sec. 2, Subd. 06c), Initiative Foundation, Voyageurs National Park, Department of Horticulture and Natural Resources (Kansas State University), and Department of Veterinary Population Medicine (University of Minnesota). The authors thank Ally R. Rogich and Linn Clarizio for their technical assistance.

Publisher Copyright:
© 2021 by American Association of Zoo Veterinarians


  • Animal Distribution
  • Animals
  • Arvicolinae/blood
  • Ecosystem
  • Erythrocyte Count/veterinary
  • Female
  • Hematocrit/veterinary
  • Leukocyte Count/veterinary
  • Male
  • Minnesota
  • Platelet Count/veterinary

PubMed: MeSH publication types

  • Journal Article


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