There are many types and species of dinosaurs that have lived together. Many scientists have questions how in the grand scheme of things each of one of them existed together and the roles they each played in their own circle of life. These scientists are called Paleobiologists. This is a very difficult field and demands detailed research of the animal remains as well as the environment that they lived in. Paleobiologists will utilize this information together and compare the animals to current animals to develop general ideas of how they lived.
Some easy identifiers of a specific dinosaurs role is found in fossil evidence. If the dinosaur had large serrated teeth, it would be considered a carnivore or a scavenger. In other words it was a meat eater. If the fossil remains had flat teeth it would have been a herbivore, or plant eater. When compared to modern day animals, this makes complete since. Traces of plants and other smaller animals can give scientists an idea of the environment in which the dinosaur lived. Perhaps it was a dense forest with lots of lush vegetation or a desert environment with minimal vegetation.
It seems that most meat eating dinosaurs were muscular and built to run. Fossilized footprints of dinosaurs have led to scientists being able to determine just how fast dinosaurs were able to run. Footprints of Ornithomimids have been found where it has been estimated that they were able to reach speeds of 25 miles an hour. Many herbivores are much larger and slower. It is thought that these animals lived in herds for protection in numbers due to many findings of multiple specimens.
With birds and crocodiles being considered phylogenetically related to dinosaurs scientists consider many of their behaviors to have also been general behaviors with dinosaurs. Many sites were eggs and nests have been found are very similar to modern day bird nesting sites. A common “strategy” among man species of birds during nesting is to nest together. This is a “safety in numbers” strategy. If there are a significant number of young that a predator can choose from the chances are greatly reduced that one of yours will be the one taken. This has been found to be true with many fossilized dinosaur nesting sites.
While it is hard to determine the true behaviors of dinosaurs, modern day media makes it even more difficult for scientists to sway an uninformed public. For instance, on “Jurassic Park”, the major blockbuster movie about scientists that actually cloned dinosaurs, the velociraptor was depicted as a pack hunter and very intelligent. In other words, the species relied on teamwork and power in numbers to take down animals much larger than themselves for the betterment of each of them, and even setting a complex trap. This was based that some carnivorous dinosaurs were found huddled together, suggesting that they were traveling or hunting together. In todays world, the most commonly believed descendent’s of dinosaurs are birds and crocodiles. Neither of these species show any behaviors associated with pack hunting. Of all of the species on Earth today, there are a specific few that do utilize teamwork in order to pack hunt, all of them being mammalians. Therefore, to assign mammalian traits should be considered questionable at best since there is no direct relationship between the two of them. While it is in fact possible that there were some species of dinosaurs that were pack hunters it is very difficult to prove.
Research:
http://dml.cmnh.org/1997Feb/msg00393.html
http://animals.jrank.org/pages/3532/Dinosaurs-BEHAVIOR-REPRODUCTION.html
