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European Journal of Wildlife Research

, Volume 56, Issue 1, pp 43–48 | Cite as

Correlates of body measurements and age in Eurasian beaver from Norway

  • Frank Rosell
  • Andreas Zedrosser
  • Howard Parker
Original Paper

Abstract

Accurate determination of age is essential for many ecological studies. Though counts of cementum annuli zones in teeth usually provide the most accurate measure of age in mammals, the technique is technically demanding, highly invasive and expensive. Consequently, ecologists and archaeologists are constantly seeking alternative methods of accurate age determination. In this study, we correlated the age of Eurasian beaver (Castor fiber) with skull length and width, body length and mass, hind foot length, tail width and length and an index of tail size to determine if these measurements were accurate predictors of age. The relationships between all measurements and age were curvilinear, making them particularly unreliable for older age classes. Skull length and width were the best predictors of age, but only individuals ≤2 years could be assigned to their correct age class with a probability >50%. However, when allowing for an error of ±1 year, the success rate of both skull measurements increased to ≥60% for females up to 4 years of age and for males up to 3 years of age. We concluded that body measurements are unsuitable predictors of accurate individual age in beavers but that especially skull length and skull width may be useful if separation into age classes such as juvenile, subadult and adult is sufficient.

Keywords

Eurasian beaver Skull and body measurements Age determination Norway 

Notes

Acknowledgements

We wish to thank F. Bergan, B. Hovde, J. I. Sanda and numerous other hunters who participated in the study and F. Bergan, R. D. Campbell and A. Fanden for preparing the skulls and assisting in measurements. The study was financially supported by the Norwegian Directorate for Nature Management; the Conservation Commissions in the counties of Telemark, Aust-Agder, Vest-Agder, Oslo & Akershus, Østfold, Vestfold, Oppland, Buskerud, Hedmark and Sør-Trondelag and the Department of Environmental and Health Studies, Telemark University College.

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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Frank Rosell
    • 1
  • Andreas Zedrosser
    • 2
    • 3
  • Howard Parker
    • 1
  1. 1.Faculty of Arts and Sciences, Department of Environmental and Health StudiesTelemark University CollegeBø i TelemarkNorway
  2. 2.Department of Ecology and Natural Resource ManagementNorwegian University of Life SciencesÅsNorway
  3. 3.Department of Integrative Biology and Biodiversity Research, Institute of Wildlife Biology and Game ManagementUniversity of Natural Resources and Applied Life Sciences, ViennaViennaAustria

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