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Incisor tooth wear and age determination in mountain gorillas from Volcanoes National Park, Rwanda
Author(s) -
Galbany Jordi,
Muhire Thadée,
Vecellio Veronica,
Mudakikwa Antoine,
Nyiramana Aisha,
Cranfield Michael R.,
Stoinski Tara S.,
McFarlin Shan C.
Publication year - 2018
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.23720
Subject(s) - gorilla , incisor , tooth wear , crown (dentistry) , national park , maxillary central incisor , orthodontics , dentistry , geography , biology , medicine , ecology , paleontology
Objectives Ecological factors, but also tooth‐to‐tooth contact over time, have a dramatic effect on tooth wear in primates. The aim of this study is to test whether incisor tooth wear changes predictably with age and can thus be used as an age estimation method in a wild population of mountain gorillas ( Gorilla beringei beringei ) from Volcanoes National Park, Rwanda. Materials and methods In mountain gorillas of confidently known chronological age ( N = 24), we measured the crown height of all permanent maxillary and mandibular incisors (I 1 , I 1 , I 2 , I 2 ) as a proxy for incisal macrowear. Linear and quadratic regressions for each incisor were used to test whether age can be predicted by crown height. Using these models, we then predicted age at death of two individual mountain gorillas of probable identifications, based on their incisor crown height. Results Age decreased significantly with incisor height for all teeth, but the upper first incisors (I 1 ) provided the best results, with the lowest Akaike's Information Criterion corrected for small sample size (AICc) and lowest Standard Error of the Estimate (SEE). When the best age equations for each sex were applied to gorillas with probable identifications, the predicted ages differed 1.58 and 3.33 years from the probable ages of these individuals. Conclusions Our findings corroborate that incisor crown height, a proxy for incisal wear, varies predictably with age. This relationship can be used to estimate age at death of unknown gorillas in the skeletal collection, and in some cases, to corroborate the identity of individual gorillas recovered from the forest postmortem at an advanced state of decomposition. Such identifications help fill gaps in the demographic database and support research that requires individual‐level data.