It has always been clear from the fossil evidence that some dinosaurs were fast and agile, with quick reflexes and sharp teeth (e.g., carnivores), while others were big, slow, lumbering lunchboxes on four legs (e.g., herbivores). To the frustration of paleontologists, though, it’s extremely difficult to find direct evidence of predation—that is, fossilized evidence of one dino eating another.
That’s why the 1972 discovery of an unusually well-preserved fossil in the Gobi Desert caused such a sensation. This find shows a sleek, long-tailed Velociraptor mixing it up with a Protoceratops; the raptor’s right arm is wedged in the plant-eater’s jaws, and its sharp lower talons are curled into the Protoceratops’ throat. Scientists aren’t sure what larger catastrophe killed these two beasts as they struggled, but one theory is that they were caught in a sudden, massive sandstorm.
Hungry, Teething Dinosaurs
To date, this Mongolian fossil is the most direct evidence we have of one dinosaur attempting to eat another dinosaur. Most of the time, paleontologists have to infer predator/prey relationships from less spectacular remains—different sets of footprints in close proximity, say, or fossils of wounded dinosaurs that went on to live and graze another day.
Not surprisingly, teeth and teeth marks are some of the best clues to who was eating whom 100 million years ago. It’s not unusual to find a predator’s loose teeth scattered among the fossilized remains of a herbivorous dinosaur (this isn’t because the attackers’ teeth were knocked out in battle; dinosaurs grew and shed teeth constantly throughout their lifetimes). Like modern-day detectives, paleontologists can also sometimes match a characteristic, fatal bite mark to the carnivore responsible—an example of very slow justice.
A Gut Feeling
One very direct (but very difficult) way to figure out which carnivores ate which herbivores is to analyze the remains in a preserved dinosaur’s stomach. A specimen of the tiny, chicken-sized Compsognathus has been found with a lizard skeleton in its stomach, clear evidence that it had recently had lunch. More disgustingly, paleontologists occasionally find carnivorous dinosaurs that harbor the remains of other carnivorous dinosaurs of the same species—meaning these dinosaurs may have been cannibals (it’s also possible that these are simply the fossils of unlaid eggs).
Sometimes it’s helpful to analyze not only what goes in, but what comes out, of a carnivorous dino. Coprolites—the preserved remains of dino poop—can be analyzed for their constituents, though the rarity of these fossils and their advanced age makes this a very dicy undertaking. For example, a large coprolite believed to have originated from a T. Rex shows evidence of bone and blood vessels—though (perhaps thankfully) there’s not nearly enough detail to determine which unfortunate dinosaur went in one end and out the other.
