2. the dinosaur reaissance

The dinosaur renaissance that started in the 1960s continued in the following decades. There was a re-evaluation of the orgin of birds which showed them to be much more closely related to dinosaurs, and an overall reappraisal of dinosaur physiology paved the path for a scientific consensus that dinosaurs were not the sluggish, cold-blooded animals they had long been assumed to be. In the 1970s the discovery of Maiasaura nesting grounds threw into question previously held assumptions about dinosaur social behaviour. The work of Jack Horner and his team at a site which came to be known as "egg mountain" revealed evidence of dinosaurs raising and feeding their young, challenging assumptions that dinosaurs abandonded hatchlings at birth. 

The 1970s also saw the first moves to depict dinosaurs with feathers. This was a contentious issue as no feathered dinosaur fossils had been discovered and evidence for the possible existence of feathers (or protofeathers) was limited to comparisons between dinosaur and bird anatomy. However all this changed in the 1990s when feathered dinosaurs were discovered in Liaoning, China. The fossils were preserved in Lagerstätte, a sedimentary deposit laid down following volcanic eruptions in the Early Cretaceous (roughly 124 million years ago). The fine grained ash persevered organisms such as insects, fish, amphibians, mammals, turtles and dinosaurs in incredible detail.