| Despite the fact that dinosaurs are now gone,
they have left us many clues that scientists use to piece together to show us what
these "terrifying lizards" looked like and how they lived. These clues are what
we call fossils (something preserved from a past geological age), and not only
include bones, but skin, nests, eggs, and footprints as well.
Dinosaur Nests
Scientists do not know how all dinosaurs reproduced, but there is evidence that
some laid hard-shelled eggs, as today's alligators do. Fossil finds of dinosaur
nests show that the Maiasaura, Oviraptor, Troodon, and Protoceratops were egg-layers.
Group Evidence
Fossil evidence shows that more than 20 kinds of dinosaurs may have occupied a particular area at the same time. Many dinosaurs, including ceratopsians, ornithopods, sauropodomorphs, and perhaps stegosaurs, probably lived in herds the year around. Other kinds, such as ankylosaurs and tyrannosaurs, may have spent most of their life alone or in small groups.
Eating Habits
Dinosaurs had a varied diet. Most of them were plant-eaters, but the theropods (bipedal dinosaurs) were meat-eaters.
Herbivores (plant-eaters) had short stubby crenellated teeth, while carnivores (meat-eaters)
had teeth that were recurved, serrated, laterally -compressed, and knife-like. The carnivores fed mostly off the herbivores.
Protection From Enemies
Some herbivores had built-in defense mechanisms to ward off predators.
The huge size of sauropods probably kept them safe from most enemies, but their smaller offspring had to stay alert to danger. Ankylosaurs had bony plates for protection, and ceratopsians and stegosaurs probably used their horns and spikes to fight off predators. Ornithopods, ceratopsians, and other dinosaurs probably gathered in herds to discourage enemies.
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