Measuring fat content using computed tomography to establish a body condition index in free-ranging blanding's turtles (emydoidea blandingii) in Illinois

Erin M. Newman, Matthew C Allender, Dan Thompson, Gary A. Glowacki, Marina Ivančić, Michael J. Adkesson, Dana M. Lindemann

Research output: Contribution to journalArticle


Health assessment of free-ranging populations requires an integrated approach, often incorporating a method to measure mass as a representation of the animals' ability to utilize environmental resources. In chelonians, direct measurements of mass have historically served as a corollary for body condition. However, this method may not accurately represent the true fat volume (FV) and may be skewed by the presence of eggs, shell size, or muscle mass. The objective of this study was to use computed tomography (CT) to develop a model for determining body condition index (BCI) in free-ranging Blanding's turtles (Emydoidea blandingii). Mass, shell measurements, and FV were measured by CT in 65 free-ranging Blanding's turtles from Lake and DuPage counties in Illinois. Twenty-one different models were built for BCI using both FV and fat percentage (FP) as dependent variables. The best fit model for FP included the relationship between mass and carapace length with nearly 60% model support. The model for FV demonstrated a similar relationship but had only 18% support. Linear models with BCI as the dependent variable showed that juveniles had a higher FP than adults and females with more eggs had a lower FP. FP can be calculated in the field with nearly 60% accuracy compared to CT-assessed FP as a component of a physical exam and population health survey to assess the effectiveness of conservation efforts for the endangered Blanding's turtle.

Original languageEnglish (US)
Pages (from-to)594-603
Number of pages10
JournalJournal of Zoo and Wildlife Medicine
Issue number3
StatePublished - Sep 23 2019



  • Blanding's turtle
  • Body condition index
  • Body fat
  • Computed tomography
  • Emydoidea blandingii

ASJC Scopus subject areas

  • Animal Science and Zoology
  • veterinary(all)

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