Fig 9. Periapical radiographs of dolphin YN9.

Even in cases where the pulp:tooth area ratio is below 0.1 and excluded from age estimation by the model; dental radiographs can help confirm other age estimation techniques. Here, dolphin YN9’s pulp area is very small (A), indicating an older animal. However, radiography shows that the single tooth extracted for GLG-based age estimation is in fact non-vital (B), and therefore likely results in a younger age estimation.