Is There Any Evidence for Cannibalism in Dinosaurs

A few years ago, a paper published in the distinguished scientific journal Nature bore an arresting title: Cannibalism in the Madagascan Dinosaur Majungatholus atopus. In it, researchers described their discovery of various Majungatholus bones bearing Majungatholus-sized bite marks, the only logical explanation being that this 20-foot-long, one-ton theropod preyed on other members of the same species, either for fun or because it was especially hungry. (Since then, Majungatholus has had its name changed to the slightly less impressive Majungasaurus, but it was still the apex predator of late Cretaceous Madagascar.) As you might have expected, the media went wild. Its hard to resist a press release with the words dinosaur and cannibal in the title, and Majungasaurus was soon vilified worldwide as a heartless, amoral predator of friends, family,  children, and random strangers. It was only a matter of time before The History Channel featured a pair of Majungasaurus in an episode of its long-extinct series Jurassic Fight Club, where the ominous music and portentous narration made the offending dinosaur seem like the Mesozoic equivalent of Hannibal Lecter (I ate his liver with some fava beans and a nice Chianti!) Notably, Majungasaurus, aka Majungatholus, is one of the few dinosaurs  for which we have indisputable evidence of cannibalism. The only other genus that even comes close is Coelophysis, an early theropod that congregated by the thousands in the southwestern U.S.  It was once believed that some adult Coelophysis fossils contained the partially digested remains of juveniles, but it now appears that these were actually small, prehistoric, yet uncannily dinosaur-like crocodiles like Hesperosuchus. So Coelophysis (for now) has been cleared of all charges, while Majungasaurus has been pronounced guilty beyond a reasonable doubt. But why should we even care? Most  Creatures Will Be Cannibals Given the Right Circumstances The question that should have been asked upon the publication of that Nature paper wasnt Why on earth would a dinosaur be a cannibal?, but rather, Why should dinosaurs be different from any other animal? The fact is that thousands of modern species, ranging from fish to insects to primates, engage in cannibalism, not as a flawed moral choice but as a hardwired response to stressful environmental conditions. For example: Even before theyre born, sand tiger sharks will cannibalize each other in the mothers womb, the biggest baby shark (with the biggest teeth) devouring its unfortunate siblings.Male lions  and other predators will  kill and eat the cubs of their rivals, in order to establish dominance in the pack and ensure the survival of their own bloodline.No less an authority than Jane Goodall noted that chimps in the wild will occasionally kill and eat their own young, or the young of other adults in the community. This limited definition of cannibalism applies only to animals that deliberately slaughter, and then eat, other members of their own species. But we can vastly expand the definition by including predators that opportunistically consume their packmates carcasses--you can bet that an Africa hyena wouldnt turn up its nose at the body of a two-days-dead comrade, and the same rule doubtless applied to your average Tyrannosaurus Rex or Velociraptor. Of course, the reason cannibalism evokes such strong feelings in the first place is that even supposedly civilized human beings have been known to engage in this activity. But again, we have to draw a crucial distinction: its one thing for Hannibal Lecter to premeditate the murder and consumption of his  victims, but quite another for, say, members of the Donner Party to cook and eat already-dead travelers to ensure their own survival. This (some would say dubious) moral distinction doesnt apply to animals--and if you cant hold a chimpanzee to account for its actions, you certainly cant blame a much more dim-witted creature like Majungasaurus. Why Isnt There More Evidence of Dinosaur Cannibalism? At this point you may be asking: if dinosaurs were like modern animals, killing and eating their own young and the young of their rivals and gobbling down already-dead members of their own species, why havent we discovered more fossil evidence? Well, consider this: trillions of meat-eating dinosaurs hunted and killed trillions of plant-eating dinosaurs during the course of the Mesozoic Era, and weve only unearthed a handful of fossils that memorialize the act of predation (say, a Triceratops femur bearing a T. Rex bite mark). Since cannibalism was presumably less common than the active hunting of other species, its no surprise that the evidence thus far is limited to Majungasaurus--but dont be surprised if additional cannibal dinosaurs are discovered soon.