Eli5: how do scientists “know” the behavior of dinosaurs without actually observing them?

Question

Eli5: how do scientists “know” the behavior of dinosaurs without actually observing them?

In: Biology

Answer 1

There’s a golden rule in biology, “Form Follows Function”, if an organism has sharp teeth, we can infer its carnivorous because sharp teeth are useful for meat but awful for vegetation. Similarly, keeled sternums are often indicative of flight due to needing the extra surface area for an attachment point of flight muscles.

Basically they look at bones and such, put a million pieces together and get an overall estimate of its niche.