Dear MARMAM community, On behalf of my co-authors, I am pleased to share our recent publication in Ecological and Evolutionary Physiology: Ho, Y.-W., Karczmarski, L., Lin, W., Lo, M.C.Y., Wu, Y., & Baker, D.M. (2024). Modeling Life History Parameters in Marine Mammals: Bayesian Hierarchical Analysis of Ontogenetic Dietary Shifts in Indo-Pacific Humpback Dolphins. Ecological and Evolutionary Physiology, 98(1), 1-16. The article is available online Open Access at: https://doi.org/10.1086/734631 Abstract: Weaning represents a pivotal ontogenetic process for mammals, marking the transition from parental provisioning to indepen- dent foraging. In monophyodont species, distinct growth layer groups that are deposited in their teeth as the animals age rep- resent a permanent chronological archive of physiological events across the animals’ lifetimes. Thus, biochemical analysis of annual dentine increments provides a means to explore animal physio- logical history. We examined the age-specific pattern, individual- level variations, and sex-related differences in dentine nitrogen isotopic values in the Indo-Pacific humpback dolphin (Sousa chinensis) using tooth samples collected from 38 carcasses that stranded ashore in the Pearl River Delta region, southeast China, between 2007 and 2018. The longitudinal isotopic records ar- chived in dolphin teeth offered insights into their foraging ecology and individual ontogenetic dietary life history. The overall pattern of d15N isotopic values in the incremental layers, analyzed under a hierarchical Bayesian framework, indicates that humpback dol- phins typically undergo an ontogenetic dietary shift (i.e., wean) before reaching the age of 3 yr (mean: 2.394 5 0.143 yr), albeit there is considerable individual heterogeneity (range: 1.548– 4.180 yr), with males consistently weaning∼3.5 mo earlier than females. Our study underscores the importance of quantifying on- togenetic parameters at the individual level, as overlooking indi- vidual variations in life history events (such as the age of weaning) may introduce biases in the broader population-level life history metrics. The application of hierarchical Bayesian modeling proved effective in quantifying individual heterogeneity and factoring it into the estimates of ontogenetic dietary shifts—an important com- ponent in analyses of broader population-level processes. Please feel free to reach out if you have any questions. Best regards, Derek ------------------ Yuen-Wa (Derek) Ho Research Scientist, Cetacea Research Institute, Hong Kong hoyuenwa[at]cetacea-institute.org