For over 160 million years Dinosaurs walked the planet, eating and being eaten in a role of survival that has existed since life began. Dinosaurs were huge, they had to eat, and they had to eat a lot, but just what (or who) did they dine on?
Dinosaur enthusiasts know that the popular image of a Tyrannosaurus Rex fighting and eating a stegosaurus were entirely impossible, the two species lived during totally different periods in history. T. Rex, as it is affectionately known, did however, eat other dinosaurs from the Late Cretaceous period.
The methods Paleobiologists use to determine what an animal ate include an examination of the fossil teeth and jaws, they study the bits of fossilized dung, fossilized stomach contents (when present), and study what food sources were available at the time.
-What the Teeth Show
Not only do teeth tell us a lot about what an animal ate, they are also one of the things we tend to find a lot of. In some cases the only evidence of a certain dinosaur are some fossilized teeth. Teeth are harder than bone, so they fossilize easier.
As you might expect meat eaters have sharp teeth for tearing into the flesh. Their teeth were serrated. Plant eaters required teeth that could strip plant matter, chew, or grind it. One of the dinosaurs with the most teeth were the Duck-billed dinosaurs, who were plant eaters. There are other shapes of teeth too, and each determines what an animal was able to eat. From finds of teeth, we have learned that some dinosaurs ate meat, others ate plants.
-What the Jaws Show
A meat eater would need a strong jaw, not only to kill its prey, but to tear off chunks of meat. The strength of the jaws of a meat eater are typically enough to break bones. Scientists can determine how muscles were attached to bone, this gives an indication of how strong the jaw would have been. A jaw that chewed in a side to side motion, would belong to a plant eater who needed this action to break down plant matter. The jaws indicate to us that again, some dinosaurs ate meat, others ate plants.
-Fossilized Stomach Contents
These are extremely rare, but can show what an animal ate in the last few hours prior to its own death. In one case a dinosaur was found with early mammalian bones in its stomach, in another a dinosaurs stomach was found to hold partially digested fish scales.
Fossils can tell us what things that were alive at the time and might have been food sources. We know from fossils that there would have been leafy plants, some of which are alive today. These fossil plants include ferns, evergreen conifers, and members of the ginko family. Of course we also know what they did not eat in terms of vegetation. Dinosaurs did not eat grass, because we know grass evolved later, after dinosaurs were extinct.
Fossilized Bones have been found showing teeth marks on them. Fields were bones were strewn and broken, also indicated predation, as opposed to cases where animals died intact.
Correctly this is called “Coprolite”, and is fossilized dinosaur poop. The problem with analyzing it, is that paleobiologists cannot really be sure what dinosaur it came from. As such they often show what was eaten, rather than by whom it was eaten. Fragments of bones, such things as egg shells, and plant matter have been found in coprolites.
We have found that some dinosaurs ate rocks, much like some birds do today. The rocks were not eaten as food, but were used in the stomach to grind up bits of food, mostly plants. These rocks have been found, and are smooth from the wear while in the stomach of the ancient beast.
-Observing Modern Animals
We know that animals eat what is easiest for them, a predator will find it easier to eat already killed, or scavenged meat. Plant eaters typically prefer fresh shoots and young saplings. We also know that plant eaters will eat insects simply by chance rather than choice.
-Just what did they Eat?
Most dinosaurs were strictly either carnivores, or herbivores, only a few species ate both types of food.
Some dinosaurs ate their own kind.
Most plant eating dinosaurs swallowed stones to help with digestion.
There were about eight times as many plant eaters as there were meat eaters, and about twice as many species of plant eaters as there were meat eaters.
We know some dinosaurs ate other animals that were alive during various time periods, such as turtles, and other prehistoric beasts no longer alive today.
We know some ate eggs or insects, although not always intentionally.
We also know that we still have a lot to learn about how dinosaurs lived, how they made kills, and what they ate.