Glossary

**Nesting behavior** refers to the suite of reproductive behaviors in dinosaurs and other animals encompassing nest construction, egg arrangement, incubation (brooding), and post-hatching parental care. In paleontology, dinosaur nesting behavior is reconstructed from fossilized nest structures, egg clutch arrangements, adult skeletons preserved in brooding postures atop nests, and the co-occurrence of hatchling or juvenile remains with adults. The diversity of nesting strategies ranges from burying soft-shelled eggs in moist substrate for passive incubation to constructing mound nests using decomposing plant material for warmth, to partially open nests where feathered theropods directly brooded their eggs with body heat. These differences correlate with eggshell mineralization (soft vs. hard), body size, and phylogenetic position within Dinosauria. The study of nesting behavior is critical for understanding dinosaur reproductive physiology, social organization, and the evolutionary origins of parental care, providing key evidence that many behaviors characteristic of modern birds originated in non-avian dinosaur lineages.