Let’s start with a definition: Dinosaurs, according to the Natural History Museum in London, were the dominant group of animals that roamed the land for between 140 and 160 million years.
Yes, all dinosaurs were egg-laying reptiles. But they were also distinct from other reptiles that lived around the same time.
For one, they had straight hind legs that stood perpendicular to their bodies. These helped them to use less energy compared with other reptiles – such as crocodiles, which have a sprawling gait.
Dinosaurs also had two holes behind their eye sockets, through which strong muscles were threaded. Because these muscles connected the jaw with the skull, they allowed for a more forceful bite.
It would seem that their categorization as reptiles is perhaps a bit overly simplistic. The more complicated answer hinges on how exactly we define what a reptile is. And to answer that question, we must revisit the dinosaurs’ downfall.