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. 2016 Apr 18;11(4):e0153648.
doi: 10.1371/journal.pone.0153648. eCollection 2016.

Age Estimation of African Lions Panthera leo by Ratio of Tooth Areas

Paula A White  1 , Dennis Ikanda  2 , Luigi Ferrante  3 , Philippe Chardonnet  4 , Pascal Mesochina  4 , Roberto Cameriere  5
Affiliations

Age Estimation of African Lions Panthera leo by Ratio of Tooth Areas

Paula A White et al. PLoS One. .

Erratum in

Abstract

Improved age estimation of African lions Panthera leo is needed to address a number of pressing conservation issues. Here we present a formula for estimating lion age to within six months of known age based on measuring the extent of pulp closure from X-rays, or Ratio Of tooth AReas (ROAR). Derived from measurements taken from lions aged 3-13 years for which exact ages were known, the formula explains 92% of the total variance. The method of calculating the pulp/tooth area ratio, which has been used extensively in forensic science, is novel in the study of lion aging. As a quantifiable measure, ROAR offers improved lion age estimates for population modeling and investigations of age-related mortality, and may assist national and international wildlife authorities in judging compliance with regulatory measures involving age.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Peri-apical X-ray of African Lion PM2.
X-ray showing outline of total tooth and pulp areas for calculating area ratio using Adobe Photoshop after Cameriere et al. (2011) [33]. Full details of the outlining and area measuring method are provided in S1 Text.
Fig 2
Fig 2. Relationship between Age and ROAR.
Plot of the dataset used in the regression process to estimate age as function of ROAR, along with regression line.
Fig 3
Fig 3. Plots of Residuals.
Plots of residuals against known ages (left, a) and of known against estimated ages (right, b) using regression model.
See this image and copyright information in PMC

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