Before there was Alferd Packer, there was T. rex

Move over Alferd Packer. There may be an even bigger cannibal in the annals of Colorado history.

A new study published Friday in the science journal PLoS One found that back in the Cretaceous period, some 65 million years ago, the mighty tyrannosaurus rex was feasting on its own brethren. Like Packer — a prospector who was accused of eating five of his companions in 1874 when they became snowbound on a trip from Montrose to Gunnison — the tyrannosaurus rex once roamed Colorado.

Yale University paleontologist Nick Longrich discovered a bone with especially large gouges in them while searching through fossil collections for another study. He fingered T. rex as the perpetrator.

“They’re the kind of marks that any big carnivore could have made, but T. rex was the only big carnivore in western North America 65 million years ago,” Longrich said in a Yale press release.

But at first Longrich didn't realize the victimized bone was also that of a T. rex. Once he did, he checked several different museum fossil collections and found a total of three foot bones and one arm bone that supplied further evidence of T. rex cannibalism. That led to yesterday's published study.

There is enormous interest in what the “tyrant lizard” (the Latin translation of tyrannosaurus rex) feasted on since it is one of the largest land carnivores of all time. One of the longer running debates in paleontology is whether the tyrannosaurus rex was primarily a scavenger or an alpha predator that gorged on other species of dinosaur.

But never before had it been seriously suggested that T. rex could have been a cannibal.

“Tyrannosaurus … seems to have been an indiscriminate and opportunistic feeder, feeding not only on herbivorous dinosaurs, but also on members of its own species,” the study reads. “It does seem improbable that tyrannosaurus routinely hunted full-grown members of its own species; however, it is possible that intraspecific combat led to casualties, with the dead becoming a convenient source of food for the victors. Still, compelling evidence for predation in tyrannosaurus remains elusive. Healed injuries in herbivorous dinosaurs are consistent with failed predation, but it is debatable whether these traces are actually the results of bites, or some other form of trauma.”

The publication notes that other large meat-eaters, particularly American alligators, are also proven cannibals. In addition to Longrich, John Horner of Montana State University, Gregory Erickson of Florida State University and Philip Currie of the University of Alberta, Edmonton, authored the study.

One of the earliest finds of tyrannosaurus rex fossils occurred in Golden in 1874 with the discovery of teeth. Since then, dozens of tyrannosaurus rex skeletons have been unearthed. One dig revealed soft tissues from the dinosaur that were found in 2005 on a ranch in northeastern Montana. The tissues were revealed when paleontologists had to break a gargantuan thighbone so it could fit inside a helicopter.

Three years ago, a study of the T. rex tissue in the journal Science connected the dinosaur's DNA to chickens, which supports the theory that birds evolved from dinosaurs.

While the revelation that the tyrannosaurus rex might have been eating its own is groundbreaking, the authors of the study said they weren't at all surprised.

“Cannibalism is common in nature,” they wrote.

River Name / Location	Stream flow, ft3/s	Gage height ft
Gore Creek
At Upper Station, Near I-70 Twin Bridges	n/a	4 ft
Booth Creek	n/a	4 ft
Abv Red Sandstone Creek At Vail	182	6 ft
At Mouth Near Minturn	223	7 ft
Beaver Creek
At Avon	21	2 ft
Lake Creek
Near Edwards	80	1 ft
Cross Creek
Near Minturn	100	4 ft
Homestake Creek
At Gold Park	127	5 ft
Eagle River
East Fork Eagle River Near Climax	n/a	2 ft
At Red Cliff	30	3 ft
Near Minturn	234	4 ft
Wastewater Treatment Plant At Avon	675	5 ft
Below Gypsum	826	5 ft
Colorado River
Near Kremmling	404	4 ft
Near Dotsero	1,630	3 ft
Below Glenwood Springs	3,140	5 ft
Near Cameo	3,740	6 ft
Below Grand Valley Div Nr Palisade	2,080	5 ft
Near Colorado-utah State Line	4,120	4 ft
Near Cisco, Ut	4,060	3 ft
At Lees Ferry, Az	12,100	9 ft
Near Grand Canyon, Az	12,200	9 ft
Yuma Main Canal Ww At Yuma, Az	1,010	10 ft
Roaring Fork River
Abv Lost Man Cr Near Aspen	n/a	n/a ft
Ab Difficult C Nr Aspen	52	1 ft
Near Aspen	78	1 ft
Near Emma	480	6 ft
At Glenwood Springs	1,180	3 ft
Hunter Creek
Near Aspen	56	2 ft
At Aspen	48	4 ft
Frying Pan River
Near Ruedi	113	2 ft
Crystal River
Abv Avalanche Crk, Near Redstone	540	2 ft
Arkansas River
Ef Arkansas R At Us Highway 24, Nr Leadville	47	3 ft
Near Leadville	86	5 ft
Below Empire Gulch Near Malta	156	3 ft
Below Granite	429	4 ft
Near Nathrop	451	4 ft
At Parkdale	464	3 ft