Was This Dinosaur a Cannibal?

Was This Dinosaur a Cannibal?

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Language: English

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in 1947 paleontologist Edwin Kolbert made a grim discovery at a site in northern New Mexico known as Ghost Ranch while exploring the high desert he and his companions uncovered the remains of hundreds and hundreds of meat-eating dinosaurs that all died at the same spot for five years Col Burt and his crew removed 13 massive blocks of rock each of which was jam-packed with dinosaur skeletons and strangely enough the vast majority of those fossils were of the same animal
00:32
Coelophysis a three metre long carnivore that lived 205 million years ago in the Late Triassic period all told at least a thousand specimens of Coelophysis have turned up at Ghost Ranch since 1947 nobody knows why or how this many dinosaurs of the same species all came to rest here but it seems that after they died their bodies were washed together possibly by a flood and the dinosaurs cause of death wasn't the only mystery that Ghost Ranch had to offer
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there was something strange about two of the adult skeletons both of them had jumbled masses of small bones bones that didn't belong to them lodged inside their body cavities to Cobert these bones looked suspiciously like the remains of other smaller Coelophysis Kolbert interpreted this as evidence of a phenomenon that's quite common in the natural world but had never before been found in dinosaurs cannibalism paleontologists have spent the better part of two decades debating whether Kolbert was right
01:34
whether Coelophysis did in fact eat its own kind and while it still has its camps on both sides the debate is important for a lot of reasons for one thing the study of these dinosaurs have given us some very rare clues about dinosaurs actual behavior something that's almost impossible to glean from the fossil record and insights into that behavior may shed some light on how extinct dinosaurs may have differed from modern-day dinosaurs also known as birds but most of all the evidence that scientists have had to study in order to
02:06
answer the cannibalism question includes some of the strangest and grossest fossils that any expert will ever get to see if you want to study cannibalism in dinosaurs it turns out you need to examine not just chewed up bodies but also fossilized poop ruptured stomachs and even prehistoric vomit cannibalism is widespread throughout the animal kingdom from polar bears to octopuses well over a thousand living species are known to do it and animal
02:37
cannibals have lots of different motivations when a male lion takes over a new pride for example he may devour existing Cubs in order to make their mothers reproductively available again Mormon crickets meanwhile cannibalize each other to get more protein and salt in their diets during their long migrations and in a study of Mexican Lance headed rattlesnakes 68% of the females were found to eat their own stillborn young possibly as a way for the mothers to replenish themselves after an exhausting pregnancy because
03:09
there are so many cannibal species alive today it might be reasonable to think that some non-avian dinosaurs ate their own - but here's the thing today's living dinosaurs birds almost never engage in cannibalism in the wild very few species have ever been observed doing it herring gulls and some birds of prey are rare exceptions so if birds aren't prone to this behavior a lot of researchers are interested in whether non-avian dinosaurs were because the answer could tell us a lot about the relationships
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between the two groups and when Kolbert examined those two Coelophysis adults from new mexico he thought he'd found compelling evidence of cannibalism for example one of the dinosaurs he found had been preserved lying on its right side and under the ribs on the creatures left flank Kolbert spotted the leg bone of what may have been a juvenile Coelophysis he also found some articulated vertebra and some fragmented bones below those ribs meanwhile the other dinosaur was lying on its left side and that creature had a jumble of reptilian bones preserved in its
04:12
abdominal cavity or at least in the space where that cavity would have been with the dinosaur was still alive so thanks to culverts landmark 1989 paper about these two specimens Coelophysis came to be depicted in TV documentaries museum exam and books as an opportunist that wasn't above preying on its own species some writers even claimed the dinosaur ate its own young but then in the early 21st century this sordid little story came into question in 2002 paleontologist Robert gay at the ghost ranch fossils
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remember the one that supposedly had a dinosaur leg in its stomach well when gay looked at the specimen he was taken aback by the proportions the leg was big the thigh bone alone was more than 13 centimeters long to him it seemed highly doubtful that the full-grown Coelophysis had swallowed such a large object in one piece that a later study of that same specimen cast even more doubt on Cole Bert's hypothesis if that leg and the other stomach contents had been swallowed you'd expect them to be sandwiched
05:16
between the dinosaurs left and right ribs where the guts were but that's not the case the left side ribs do lie on top of the mixed-up fossils but the right side ribs aren't underneath the fossils instead they're pulled backward and that's because paleontologists now think that after it died the dinosaur basically exploded it could have happened because the weight of the sediment on top of it or because of gases that built up in its gut after it died but it appears that the abdominal cavity of this Coelophysis ruptured
05:47
which makes it hard if not impossible to determine what was in its stomach so then what about the other skeleton well it passed the rib test the left and right ribs did actually in case at least some of the bones inside the abdominal cavity Plus this dinosaur had intact gashed raelia gastrula r rib like bones that line the bellies of many dinosaurs in life they weren't attached to the rest of the skeleton so they tend to get lost very easily during the fossilization process but since this Coelophysis still had its gastrula and
06:19
ribs intact that meant that it probably hadn't exploded which is nice because it means that the bones found in between its ribs must have come from the animals at eight however when researchers took a closer look at those bones they couldn't find a single fossil that definitely came from another Coelophysis among the few bones that could be identified a couple closely resemble those of hesperides a fast moving relative of today's crocodiles that lived alongside the dinosaurs at ghost ranch so it seemed like the dinosaur had eaten other reptiles before it died but
06:50
there was no evidence that it engaged in cannibalism after years of intense study of those two specimens the reputation of Coelophysis seemed to have been restored until the debate took an unexpected and even more graphic turn while much of that work was going on another group of paleontologists working with the New Mexico Museum of Natural History in science was examining a separate block of Coelophysis skeletons from Ghost Ranch and they had found that one of the adult skeletons in there had a lump of prehistoric poop lodged between the base
07:21
of its tail and its hip bones normally fossilized poop samples are called coprolites but given its placement the scientists think this could be a Cola light which is basically a preserved hunk of partially digested material that was never excreted just 10 centimeters long by 6 centimeters wide and 1 centimeter thick this trace fossil was loaded with hundreds of bone fragments bet you didn't think you were gonna get that good of a description of a piece of poop today among these the team discovered wrist and hand bones that
07:52
looked identical to those seen in juvenile Coelophysis skeletons plus the scientists later found what appeared to be another totally unexpected in a pretty gross trace fossil fossilized dinosaur vomit fossils of vomit are indeed a thing although they're extremely rare and they've been dubbed regurgitates and some of those traces of ancient barf were found in and around the mouth of another adult Coelophysis from ghost ranch and inside the prehistoric puke researchers found tiny little teeth that
08:23
resembled those of a young Coelophysis so between the poop and the vomit we may finally have evidence of cannibalism in this dinosaur as always there are those that disagree but if it's true that Coelophysis ate its own kind it probably wasn't the only dinosaur that did majungasaurus was a 6-meter theropod that terrorized madagascar in the Late Cretaceous period and its bones are sometimes found with bite marks that perfectly match its own teeth in terms of shape and placement since no other carnivores
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it's sighs have been found around it in fossil beds paleontologists are fairly confident that the junga source regularly fed on members of its own species and then there's our old pal t-rex a 2010 survey of Tyrannosaurus Rex fossils concluded that at least four different specimens showed direct evidence of cannibalistic behavior the evidence again was bite wounds on their bones that matched t-rex teeth and while there's evidence that some dinosaurs bit each other during combat there's no evidence that these bones healed after they were bitten which suggests that
09:24
they were chewed on after death now this leaves us with the big question why would dinosaurs like Coelophysis and t-rex eat their own kind especially when there's almost no record of avian dinosaurs doing the same thing as with cannibalism and other organisms it could have happened for many reasons perhaps it was a last resort when food was scarce or maybe it helped limit competition much like modern American alligators are known to eat juveniles of their own species to eliminate future competitors and some animals from alligators to water bugs have also been known to engage in cannibalism as a
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means of population control Plus even if these dinosaurs did eat each other we still don't know if they were actively hunting each other or just scavenging on each other's corpses but all told the decades-long debate about Coelophysis and cannibalism goes to show you that with solid detective work and a willingness to rethink our assumptions we can get better at reading the strange clues we find in the fossil record and that brings us closer to understanding the ghosts of the prehistoric past from ghost ranch and beyond
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I'd like to thank two paleontologists Spencer Lucas of the New Mexico Museum of Natural History in science and Sterling Nesbit of Virginia Tech for their help with this episode and I also want to thank this month's Yount ologists Patrick Seyfert Jake Hart John Davison Inge and Steve if you'd like to join them and our other patrons in supporting what we do here then go to patreon.com your pledge and finally thank you for joining me today in the Konstantin Haase studio if you want to join us for more adventures in deep time just go to
10:58
youtube.com slash Ian's and subscribe [Music]

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