Abstract Assigning ages to lions (Panthera leo) requires the use of subjective and objective criteria, and is useful for conservation decision-making in that age distributions can be defined from which demographic profiles can be extracted. We collated all age assignment criteria and found that a constraint of most objective criteria is that they require immobilized or dead specimens to measure. Furthermore, nearly all criteria used lions with assumed ages to construct relationships or narrative descriptions. We show that digital photogrammetry provides digitally-derived measures of shoulder heights similar to that of linearly derived measures. In addition, such shoulder heights did not differ between captive and free ranging lions, or between different regions in Africa. Variation in shoulder height is primarily associated with sex-specific age. Age, using the von Bertalanffy growth curve, explained 92% and 97% of the variation in female and male shoulder height, a skeletal measure not strongly affected by resource availability. Simulations suggest that age assignment is relatively accurate for females and males with shoulder heights up to 70 cm and 95 cm, respectively. Thus for lions younger than two years of age objective criteria gives most precise estimates, while subjective criteria are more suitable for older lions.

Yes / Background: stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in bone and dentine collagen have been used for over 30 years to estimate palaeodiet, subsistence strategy, breastfeeding duration and migration within burial populations. Recent developments in dentine microsampling allow improved temporal resolution for dietary patterns. Aim: We propose a simple method which could be applied to human teeth to estimate chronological age represented by dentine microsamples in the direction of tooth growth, allowing comparison of dietary patterns between individuals and populations. The method is tested using profiles from permanent and deciduous teeth of two individuals. Subjects and methods: using a diagrammatic representation of dentine development by approximate age for each human tooth (based on the Queen Mary University of London Atlas) (AlQahtani et al., 2010), we estimate the age represented by each dentine section. Two case studies are shown: comparison of M1 and M2 from a 19th century individual from London, England, and identification of an unknown tooth from an Iron Age female adult from Scotland. Results and conclusions: The isotopic profiles demonstrate that variations in consecutively-forming teeth can be aligned using this method to extend the dietary history of an individual, or identify an unknown tooth by matching the profiles.