Accuracy and precision in estimation of age of Norwegian Arctic polar bears ( Ursus maritimus ) using dental cementum layers from known-age individuals

摘要: Validation of age estimation from tooth cementum growth layers was conducted for 32 polar bears (Ursus maritimus) known age, by two readers. Both readers correctly estimated 24% the bears, and 50–53% were within year correct age. The young animals (age 1–8) overestimated, while ages over 8 years underestimated. Comparison between readings indicated that precision low. Further, one reread slides earlier prepared read another laboratory. There a large discrepancy these indicating bias in estimated. We conclude can be difficult, particularly populations where individuals may forage throughout year. As deposit differently different areas, as laboratories same according to criteria, an evaluation methods should all populations, based on significant number slides, with broad range,