T-Rex really was a cannibal – making the king of the dinosaurs even scarier.
A bone broken half dug up in the United States had such huge teeth marks it could only have been gnawed on by one of its own, according to new research.
Scientists say the find in Wyoming lifts the lid on a “nasty little 66 million-year-old family secret” – that 35 ft long T-Rex ate each other as well as smaller dinosaurs.
It has been suggested before that the legendary carnivore may have been into cannibalism – the last taboo for humans – but the new find has been hailed as the best evidence yet.
Paleontologist Matthew McLain, of Loma Linda University in California, said: “This has to be a Tyrannosaur. There is just nothing else that has such big teeth.”
The grooves in the bone were clearly those of an animal pulling the flesh off the bone in a perpendicular direction, in the same way humans eat a piece of fried chicken.
Getty
But one stood out. It was located at the larger end and contained smaller parallel grooves caused by the diner’s head turning, so the serrated edges of its teeth dragged across the bone.
McLain, a PhD student, explained: “We were out in Wyoming digging up dinosaurs in the Lance Formation.
“Someone found a Tyrannosaur bone that was broken at both ends. It was covered in grooves. They were very deep grooves.”
The serrated teeth ruled out crocodiles and pointed directly to a theropod dinosaur, like T-Rex.
The fact the only large theropods found in the Lance Formation are two Tyrannosaurs – T-Rex or Nanotyrannus lancensis, eliminates all interpretations but cannibalism, said McLain.
He will present the discovery on Sunday at the annual meeting of the Geological Society of America in Baltimore.
The direction of the grooves is consistent with getting flesh from bones off an animal that was quite dead at the time. The bones don’t reveal whether the cannibal was scavenging or was also the killer of the Tyrannosaur.
McLain said: “Exactly who did the eating that day, in the Late Cretaceous, could still be sorted out by the same grooves.”
The serration grooves are a valuable clue to the size of the animal who owned the teeth.
Previous work using Komodo dragon teeth has demonstrated the relationship between serration sizes and the size of the animal.
This approach has been used on tyrannosaurs, and McLain thinks it will work in this case, too.
He said: “It only works if you know what species it is. And since Tyrannosauruses are the only large predators in these formations, it is pretty straightforward.”
Even without knowing the size of the eater, it may be easy to say which species of tyrannosaur was eating, because, according to McLain, many paleontologists believe Nanotyrannus was really a juvenile T-Rex.
Previous fossil evidence has suggested T-Rex was a cannibal. The giant predator may have eaten its victims after battles, with the victors consuming the losers. It is believed it craved meat so much it ate individuals from its own species.
Only one other dinosaur, Majungatholus, is known to have engaged in similar behavior, but paleontologists believe Gorgosaurus, another huge meat-eater, and many other gigantic predatory dinosaurs were also cannibals.
A lot of large carnivores tend to be cannibals including lions, hyenas, alligators and polar bears. They are equipped to kill and eat large animals, so fellow members of their species are just one more kind of large animal.
Some scientists say the dino-on-dino feasting happened after fights, a meal that would help the cannibal victor because you are killing a competitor and getting a free meal at the same time.
The hunting is going to be better if you eat the other hunters.
Battles between mega carnivores would have been quite a spectacle, with them attempting to clamp down on their opponent’s neck or jaws to prevent them from fighting back.
