Bone histology is the study of bone function and growth by sectioning bones into thin slices to visualize internal tissues. This technique has proven instrumental in uncovering the physiology and ecology of extinct animals, providing insights into their growth rate, age, metabolism, and degree of aquatic adaptation — factors that were previously challenging to reconstruct. My research focuses on employing bone histology to explore the life and adaptive processes of large vertebrates, such as dinosaurs and mammals. Specifically, I aim to uncover what factors influenced these creatures to evolve into giants or diminutive forms and how terrestrial vertebrates altered their physiology and bone structure to successfully readapt to aquatic environments.