Of course, the parental care traits of dinosaurs cannot be directly observed because they’ve been extinct for 65 million years. Therefore, paleontologists have had to resort to observing the closest living relatives of the dinosaurs: birds and crocodiles. They believe that these modern animals probably had many of the same traits, including construction of nests or mounds, nesting together in rookeries, guarding the nest by one or both of the parents, warning and recognition sounds made by the young, and family group cohesiveness during the hatchling stage. In fact, many of these traits have been confirmed by recent fossil findings.