T. rex vs. Prey: Imagining battles between ancient gladiators

When I was super young, say around five or so, I remember playing in the bath tub with my plastic toys. Some were super heroes like He-Man or Teenage Mutant Ninja Turtles, others were monster trucks and die-cast matchbox cars by Mattel, but most were dinosaurs.

This might be TMI, this story about the kid in the bath tub with bubbles on his head, ramming plastic characters into one another and dreaming up their backstories, the bellows of challenge they traded, and the choreography of their battles, but I know there are other adult children out there with similar memories.

During this epoch in the evolution of me, I distinctly recall pitting Tyrannosaurus rex against Stegosaurus, which, as I’ve discovered in later life, was completely wrong, as was most of what I thought around five years old, but you know, who can blame a five-year-old for muddling up the fossil record?

T. rex is one of the most famous dinosaurs in history, easily identified by its massive, heavy skull, long steak-knife teeth, powerful back legs and tail, and ridiculous vestigial arms, but due to her status as dinosaur royalty, the length of her reign and her identity is as often confused by adults as it is by naive five-year-olds. The T. rex lived for two million years in the Late Cretaceous, never in the Jurassic, as her appearance in Jurassic Park might suggest, but we can forgive this fiction for its oversight. (After all, InGen, the engineering firm responsible for cloning extinct dinosaurs in the movie, infamously mismatched animals from different eras within the same park.) And she wasn’t the only two-legged carnivore.

stego allo

In a dramatic representation, Stegosaurus and Allosaurus duke it out in the Jurassic. Morian Hall.

In the time of Stegosaurus, between 155 and 150 million years ago (the real Jurassic), the apex predator was the Allosaurus. Smaller than the T. rex, but with more capable arms with three fingers ending in talons, this baddie no doubt picked battles with Stegosaurus, putting its life on the line for a meal. With its polygonal plates down its back, viciously spiked tail, flexible spine and toes that allowed it to rear up, Stegosaurus could give Allosaurus a true walloping.


Allosaurus remains feature prominent eyebrow ridges and three-fingered hands with sharp claws.

Forget about jaws and claws. One solid hit from the bone spikes could deeply puncture the neck or torso of any shady Allosaurus looking for a bite, and its plates would protect its spine from being severed by teeth until it could land a blow. It isn’t difficult to imagine eyes gouged and jugulars perforated, many Allosauruses bleeding out after botched predatory encounters with Stegosaurus. There were certainly easier things for Allosaurus to eat, but few battles with other species could match the gladiatorial epicness of this match-up, at least not in this era.


Even as an herbivore, Stegosaurus would have made a formidable opponent against Allosaurus in the Jurassic, using a spiked tail and bone plates along its spine as defenses.

Fast forward 90 million years to the Late Cretaceous, the reign of the “tyrant lizard.” Tyrannosaurs roamed North America and Asia, preying on a variety of other famous megafauna like Triceratops, Ankylosaurus, and duck-billed hadrosaurs including Edmontosaurus, Brachylophosaurus, and Parasaurolophus. There’s no way T. rex even knew Stegosaurus was a thing. More time passed between these two than between dinosaurs and Homo sapiens.


As the largest predator of the Late Cretaceous, the T. rex is one of the fossil record’s most iconic species.

Nor was the T. rex the only one of her kind; she was just the largest, hence the name, “king of tyrants.” Among her smaller contemporaries, Tarbosaurus, Albertosaurus, Daspletosaurus, and Gorgosaurus, she was the Queen B, big and bad, in spite of the competition. She had excellent vision, a sense of smell that could detect prey from miles away, and decent hearing, though high-pitched sounds would have been lost to her. Food wouldn’t have been difficult for the T. rex to find, but that food really, really didn’t want to be eaten.


T. rex couldn’t have fought Stegosaurus, but it preyed upon Triceratops, another iconic species that lived in the same time period.

There’s no more famous match-up than Tyrannosaurus rex and Triceratops. With two long horns and a bony frill like a samurai helmet to guard its neck, as long as the trike met the T. rex head-on, there was no contest. But if Triceratops charged and missed the mark, the tyrant’s big jaws could take out its backbone in a single bite, neutralizing the threat of horns. Recent discoveries of casts of Triceratops‘s hide reveals nodules that might have housed quills, making even a bite to its back a dangerous one if T. rex ever got around the impenetrable helmet. You can imagine this battle yourself in the Morian Hall of Paleontology, where Lane the Triceratops takes a defensive position under an aggressor T. rex.


T. rex preyed upon Denversaurus and its famous cousin, Ankylosaurus, but both would have made a difficult meal, protected by bony armor.

Against Ankylosaurus and its cousin Denversaurus, also on display in Morian Hall, tyrannosaurs likely had a more difficult time. Both Ankylosaurus and Denversaurus developed the adaptation of a wide, low body and armored plating, making access to its soft underbelly impossible for tyrannosaurs unless kicked onto its back, but Ankylosaurus had another advantage. The tip of its tail bore a mace-like club that, like Stegosaurus’s spiked tail, could maim the jaws of predators that didn’t pay enough heed. One swing from this heavy weapon could break open a T. rex‘s face, cripple its legs, or shatter its ribs, and with arms too small to defend itself, dodging seems the only tactic at her disposal against this tank of a creature. An encounter with an Ankylosaurus could mean either a meal or certain death, depending on the T. rex‘s experience hunting.


Armor plating on the back of Denversaurus would have protected against a bite from the T. rex and other tyrannosaurs of the Late Cretaceous, but if flipped over, its soft underbelly would be exposed.

A more easy meal for any tyrannosaur would have been Edmontosaurus and other duck-billed dinosaurs. These hadrosaurs had few defenses. No armor plating, no spikes, no claws, no wings, no sharp teeth. But it’s possible they had a different advantage, though it’s tough to deduce through fossils alone. Hollow chambers in the skulls of many hadrosaurs suggest these creatures, like geese and other water fowl, had the power of sound at their disposal. A deafening bellow might have stopped a tyrannosaur in its tracks or sent it running in the other direction. T. rex isn’t known for its sensitive hearing, but as we all know, if the sound is loud enough, it can be excruciating. And T. rex had no fingers to put into her ears, nor could she reach them.


Edmontosaurus, a duckbilled hadrosaur and cousin of Parasaurolophus, appears to have lacked natural defenses. However, the hollows in its skull suggest it could have protected itself with deafening bellows like giant geese.

Understanding these species as they once were, interacting with one another, is more than bath tub child’s play for paleontologists; it’s a career and a discipline. It’s in the Greek roots of the word “paleontology,” the study of being and beings in the ancient world. The study of what life on Earth might have looked like eons ago. The work of these scientists is more like philosophy than fiction, but building careful theories via the fossil record and considering every angle does require a measure of imagination.


An artist’s representation depicts Triceratops and Tyrannosaurus rex in an age-old feud set in the lush swamps of the Late Cretaceous, an imagined scene deduced from evidence in the fossil record. Morian Hall.

I suppose, apart from the spikes and teeth and horns and claws and body armor and all the other things that make these terrible lizards seem like something out of science fiction, or monsters invented by a puppeteer, it’s the daydreaming paleontology requires that holds my attention. To understand their world, you must build it in your mind.

The Greatest Dinosaur-ologist Ever! The Reverend Edward Hitchcock.

Congregationalist Minister, Director of the Massachusetts Geological Survey, and First to Prove that Dinosaurs Had Feathers.

Part Two: U-boats and the Knuckle Decipherment.
(Read Part One Here)


Ferocious Flat-foots frighten second grader. A cartoon from Punch 1855 shows three dinosaurs restored at the Crystal Palace as big-shouldered and flat-footed. Supposedly kids were dragged kicking and screaming through the rows of monstrous sculptures.


Last year we left our dear friend, the Reverend Hitchcock, footprint sleuth of the 1830’3-50‘s, close to solving the riddle of the track-makers who stomped all over his Jurassic landscape. It wasn’t just a local New England puzzle. Similar tracks were excavated in Europe, Asia, Africa, Brazil — everywhere sediments were dated to the Jurassic, Late Triassic and Cretaceous. Hitch knew these beasts were bipeds, striding swiftly across muddy flats and sand bars, holding their heels high off the ground. Could they have been dinosaurians?

Absolutely, positively NOT! All the wise men of paleontology said Hitch’s tracks were totally, completely, astoundingly different from the imprints that would be made by a real-life dinosaur. All the textbooks and monographs said that dinos were flat-footed quadrupeds, and that’s the way they were restored as life-sized sculptures in the Crystal Palace Exhibition in a park just outside of London in the 1850’s. The 3-D dinos proudly displayed all the latest discoveries from the very best minds in Europe. This exhibition was the first “Jurassic Park” style extravaganza anywhere. Record crowds came and gawked at the Jurassic and Cretaceous behemoths. Three separate dino species were shown in giant models, plus assorted extinct crocs, ‘dactyls and sea-reptiles. All three dinos were shown as pentadactylus flat-footed monsters. All had forefeet as big as their hind feet and monstrously muscled shoulders. All the officially sanctioned dino-models on sale at the gift shoppe were five-fingered and five-toed too.

You could buy posters of the dinosaurian flat-foots and tiny miniatures cast in lead to act as paperweights or kids’ toys. Textbooks and encyclopedias were swayed by the exhibit and carried the same anatomical message. The Dinosauria as a group had legs like bears, with forepaws designed to excavate holes and bring down prey with one swipe of the claws. Tracks made by such beasts would, of course, display five digits fore and aft. The footprints had to leave big flat-footed sole marks too. Therefore, Hitchcock’s track-makers couldn’t be dinos, everyone knew that. Hitch’s favorite Jurassic critters had three main toes in the hind paw, arranged so the middle toe was the longest. Hind feet were gigantic, dwarfing the front paws in the few species who came down on all fours. Nothing could be more different from what science had discovered about dino paws.


Don’t be misled by the cryptic title. Here’s the best book on the Enigma Machine during World War II. Read this book to get the true story of Alan Turing and the cracking of the Nazi U-Boat code, as portrayed in the hit movie “The Imitation Game”

Triumph of the Congregationalist Mind: The digital decipherment. 
There was a puzzling disconnect between what the bone-scientists said and what Hitch and his fellow track-analysts were thinking. The bone guys saw dinosaurs as the commonest big land animals of the Jurassic, and the dinos were four-legged flat-foots, so they thought. Oddly, no one could find fossil footprints that matched the dino reconstructions. There were no giant flat-footed tracks in the rocks that contained giant dino skeletons. Odd, very odd.

Hitchcock ignored dinosaurs as they were reconstructed in Europe. He focused on bringing back to life the bipeds who had left behind the spectacular tracks in New England. To realize his life’s goal he needed to “see” the foot skeletons of his track-makers. But he had no fossilized pedal petrifications. No ankle bones; no toe bones, no fingers. He needed a miracle. He needed time-traveling x-ray vision that would reveal exactly where each and every bone fit in each and every toe. Congregationalists didn’t believe in miracles, not in the normal course of scientific work. What Hitchcock believed in was the power of the analytic mind and the beautiful regularity in the design of Nature. Here all his sole-searching paid off big. He already possessed the best set of diagrams of feet from living species, thanks to all the time spent chasing critters across muddy fields. Now he needed to sit down and search for the key that would unlock the skeletal.

Hitch succeeded. He cracked the code of the tracks. This decipherment must stand as one of the most heroic triumphs in the history of de-encryption, right next to the cracking of the U-boat signals sent by World War Two’s Enigma Machine. That Enigma Code story is told in the movie “The Imitation Game” with Benedict Cumberbatch playing the math genius Alan Turing. During the early days of the war, England was being starved by the U-boat offensive.Cargo was being sunk so fast that food, ammo, and guns were running short. The key to the U-boat success was the system of commands coming from German naval headquarters, sent in a new code that was diabolically complex. Each message was encrypted by the “Enigma Machine” that scrambled and double scrambled and triple scrambled every word.

Turing and his crew were told “The Enigma Machine is impregnable — no one can figure it out.” The crew took that as a challenge. They triumphed! (Note: it was more of a team effort than shown in the movie). Soon the Brits were reading the Nazi messages before the sub commanders did. U-boats were intercepted. Depth charges were dropped with precision. Salvos of hedgehog rockets were fired (Google “hedgehog”). The undersea threat was neutralized.

uboatMs. Emily Dickinson and a World War II U-boat.  The U-boat is at the left. To learn more: “Dickinson, Selected Poems and Commentary” by Helen Vendler, 2010, Harvard University Press.

I imagine Cumberbatch or maybe Anthony Hopkins playing Hitch in the movie “Dino-Code Breaker”. I see Hitch hunched over his drawing board surrounded by pickled feet of local newts, frogs, toads and a bandicoot paw sent from Captain Cook’s explorations. Angelina Jolie, plays poet Emily Dickinson, a frequent visitor to the Hitchcockian lab. She brings him a cup of tea and a translation of a French monograph on mole feet. The candles burn down to their pewter holders. Light flickers.

“I’ve GOT IT!” Hitch leaps up, waking up Ms. Dickinson who was snoring in a rocking chair. “See…..it’s all in the knuckles! All in the pads under the joints.” Emily stares at the diagrams for a few seconds….

“Yes, I see it too. The Law of Knuckles!!!! There’s a single pad under each joint where two toe bones meet.”


Knuckle pads on the tracks of a squatting Anomoepus.

Hitch’s breakthrough came via one very special track-maker whom he had named Ano-moe-pus, meaning “Uneven Paws”. This is the species that occasionally squatted down and put its forepaws on the mud. There were three big hind toes pointing forward, the longest in the center, and a little one pointing inward. It’s knuckle-pads were exceptionally well defined so Hitch could see exactly where bones came together at each joint.

The little toe had just one pad — that meant it had just two separate toe bones meeting at the pad. There was a sharp claw protruding from the pad. We paleo-podiatrists use a formula, a digital short-hand, to express the toe-bone design. We number toes from the inside to the outside, so the human innermost toe (we call it our “big toe”) would be Toe I. The pinkie toe is Toe V. The middle toe, of course, is Toe III. Using the formula, we can say that Anomoepus Digit I had 2 toe bones, or to be technical, two phalanges (phalanx is techno-speak for toe bone; plural phalanges).

The next toe in Anomoepus, Digit II, had two pads = three phalanges. Digit III, the longest, had three pads = four phalanges. Digit IV had four pads = five phalanges.

I imagine beads of perspiration trickling down the Reverend’s forehead as he wrote down the toe formula for Anomoepus. He sensed that he’s close to the answer for all his mystery tracks. When done with Anomoepus, he had a digital formula of 2-3-4-5. What about the pinkie toe, Digit V? No pads, no claw. No toe bones. Score the pinkie toe as a big 0. Hitch’s mystery beasts had no pinkie toe!! 

Final formula: 2,3,4,5,0. That was a huge advance in eliminating suspects. Mammals were out. Basic mammal formula is 2,3,3,3,3. Never did mammals have more than 3 phalanges on any toe, so therefore Hitchcock could ignore any suspect that was furry. (Don’t take my word for it. Take off your socks and count your toes. Now do the same for a relaxed kitty or ‘possum).


Jurassic Enigma Machine. Each pad is where two bones met….so filling in the foot skeleton was easy. Anomoepus has a formula of 2-3-4-5-0

No way the track-makers could be five ton bandicoots and kangaroos. Frogs? Nope. They never had more than four phalanges in the hind toes.

Lizards? They did have more than 3 phalanges in their middle digits, but they usually had a pinkie toe and so carried the formula 2,3,4,5,3. Hitch’s memory ran through all the paws he’s examined. Who had 2,3,4,5,0 Interesting. Alligators! Crocodiles! Closer than lizards but these formidable reptiles had wide, flat feet. And their inner toe was too big and pointed forward. And and…..crocs and gators didn’t go about on their tippy-toes and didn’t run on hind legs alone.

Hitch was very, very careful, testing and re-testing any theory of the crime scenes in the Jurassic rocks. He didn’t make a rush to digital judgement. I see him pushing back back on his desk chair, smiling. He looks over to Emily Dickinson and nods. She nods back.

“….birds…” They say in unison, in still soft voices. “The mystery monsters are birds.”

BRILLIANT!!!!! Totally awesome — that was the very first time the foot of an extinct beast was correctly envisioned, without a single bone. Problem? The biggest track-makers were over ten times bulkier than the heaviest ostrich, judging from the track size. Hard to believe? Well, no; there was precedent. Richard Owen, most famous paleontologist of the time, had announced fossil birds from New Zealand – the “Moas” — that were so huge they must have reached a ton or so. And the complete hind feet looked exactly like thick, heavy duty versions of Hitch’s Anomoepus. Moas had survived almost to the present day before the Maori hunters wiped them out. It could be that the moas were remnants of a world-wide Jurassic ground-bird dynasty.


Big bird, recently extinct. Hitchcock’s diagram of a moa foot and a moa exhibit at Moscow’s paleontological museum.

In 1858 Hitchcock’s careful, exquisite scrutiny of all things digital and phalangeal won praise from colleagues all over the scholarly globe. “He’s done it! He’s proven that a great Subclass of Flightless birds ruled the Jurassic.” There were only two lingering problems for Hitch’s theory:

Where were the wings? In the specimens with front paw prints, there were five short fingers. Bird wings have three long fingers (check the bucket of buffalo wings next football game). Hitch had to conclude that his Jurassic avians were flightless and used their stubby-fingered hands for digging, not flying.

The second problem was the tail. There were imprints in some Anomoepus specimens that might be from a long, thick tail. Birds today never have much of a tail and never with long bones and massive muscle. But maybe the Jurassic birds did have a mighty caudal appendage?

Both problems got solved by a skeleton dug in 1862, from a Jurassic quarry in Germany. A delicate raven-sized skeleton was a near perfect match for Hitchcock’s prediction of a Mystery Track-maker: the hind legs were long, especially in the ankle; the hind foot had a 2-3-4-5-0 layout; and the front paw had claws on the fingers. The rear end was wonderful; there was a long, strong, bony tail. Skeleton-wise, the little fellow was a fine example of a small Anomoepus.

Judging just from the leg bones, Hitch would’ve called the German specimen a bird. Ah…and here’s the delicious part. The skeleton came with skin, preserved as clear imprints on the limestone. The skin had feathers. Big flight feathers on the arms, wide feathers all along the tail. Yes indeed, this Anomoepus-like animal was clothed in feathers. The critter received the name Archaeopteryx.

Even more emphatic validation of Hitchcock came in 1866-68 when T. H. Huxley visited his chum John Phillips at Oxford University to talk over megalosaurs. As they pondered megalosaur legs, the two men exposed a case of osteological malpractice. Remember that Megalosaurus was a Jurassic meat-eating dino of large size. The bones were jumbled up by scavengers before burial, causing confusion — it wasn’t totally clear what belonged to the front end and what belonged to the rear. The English paleontologists in the 1820‘s and ‘30’s decided that the big, flat bone was a shoulder blade and the long skinny bone was a collar bone. That’s why the reconstruction showed immense forequarters and arms as fat as a bear’s.

Though most anatomists agreed, the restoration had serious front-end alignment issues. Professor John Phillips and T. H. Huxley showed that the giant shoulder bone of the Jurassic Megalosaurus was, in fact, a giant upper hip. And that hip that was very bird-like. The real megalosaur shoulder blade was narrow and bird-like. The real megalosaur hind feet weren’t five-toed and flat. They were arranged according to the pattern worked out by Hitchcock for Anomoepus. Properly restored, the megalosaur was a giant version of Anomoepus, just as Archaeopteryx was a mini-version. Megalosaurs had the exact body build necessary to make the biggish tracks studied by the Reverend.


Putting the hips where they belonged — painting by Luis Rey.


A hypsilophodont dino — feet matched Hitch’s Anomoepus.

More complete skeletons were dug for other dino families. The hypsilophodonts, smallish plant–eating dinos, had front and back feet that matched Hitch’s beloved Anomoepus tracks perfectly. At last it was clear that Hitchcock had been studying dinosaurs all along, starting in the mid 1830’s. He was dead right about the mystery monsters being built like birds and moving swiftly in flocks over the ground. All the European savants had been dead wrong when they stuck flat-footed paws and muscle-bound bear shoulders on their dinos.

Sadly Hitch had gone to his reward before the textbooks were rewritten. He received surprisingly weak posthumous praise. When I took paleo courses at Yale in the 1960‘s, Hitch got hardly a mention. Most dino-books even accused him of making a mistake when he called his track-makers “birds” instead of “dinosaurs”. No he didn’t make a mistake! He was right!! The track-makers were part of the avian family tree. All dinos were.

And therefore we dinosauro-philes of the 21st century must make amends. We doff our hats and give the credit where it’s due.

Mebbe…….we should write letters to Universal Studios and ask that they give a percentage of the billions made by the “Jurassic Park” franchise to the Massachusetts Geological Survey and to the Congregationalist Church of America.


* No one called him “Hitch” in public when he was alive. Still, he was so humble and accessible to students that I think, were he with us now, the nickname would have been ok.

p.s. Emily Dickinson’s (ahem) U-Boat poem

There’s no Book like an Unter-Boot
To drop us deep at Sea
Nor any Poetry as Perilous
As the Torpedoes’ stealthy speed —
This Traverse may the greatest take
And oppress them with the Toll
How deadly is the Chariot
That hunts the Human Soul.

A Tale of Two Compys: What Jurassic Park got right — and wrong — about dino anatomy

Bakker - Dino Geek JP 1

A piece of unapproved Ivy League art. Title: Podokesaurus holyokensis, Triassic/Jurassic Dinosaur, on the head of Michelangelo’s David. Material: Collage of Xerox images, clipped by scissors, Scotch taped together.  Date: March, 1964.  Artist: Robert Thomas Bakker, Yale freshman.

OMG I was such a dino-geek in college.

I had other interests — I was enraptured by sculpture and took the fabled freshman History of Art course. The collage shown here was taped together during the lectures on the Renaissance renewal of anatomically correct human form made famous by Greek sculptors. Last month, I found the collage in an old notebook, in the garage, under my copy of American Battleships, a Design History. (That’s for a future blog on the U.S.S. Texas.)

The tiny dinosaur is Podokesaurusat the time, one of two famous bantam-weight predators of the Late Triassic and earliest Jurassic, the first chapters in dinosaur history. I knew the critter well because it was dug from the red beds of the Great Triassic/Jurassic Valley. Those fossil-rich sandstones and shales filled a rift valley that extended from Nova Scotia to the Carolinas. The rift was as big as the East African Rift we see today.

Smack dab in the middle of the Triassic/Jurassic Valley was New Jersey, where I grew up. Not far north from my house were the Palisades and Granton Quarry, where Triassic flying reptiles had been discovered, plus long-snouted phytosaurs like our HMNS Smilosuchus, plus dino footprints.

The reason I applied to Yale was mostly because it had a museum chock full of red beds specimens. When I visited in 1963, Yale had a cast of the podokesaur skeleton on display — sadly, the original was destroyed by fire 50 years previously. Next to the cast was a lively life-sized sculpture, done by the Yale curator Richard Swann Lull.

“Nifty!” I thought. “Art and paleontology combined! This is the place for me.” The Yale museum was super hospitable to freshmen. I got a job cleaning a Triassic red beds skull — not a dino, but a bizarre plant-eating reptile, woodchuck-sized, with spikes coming out of the head like a tricked-out horned toad. These fellows must have lived in colonies. A bunch were dug from a small area in New Jersey. Podokesaurs surely chased these prickly morsels.

Late Triassic, New Jersey. A colony of vegetarian Hypsognathus emerges from their burrow. Maybe they had been hiding from podokesaurs, Maybe they had been watching Jersey favorite “The Sopranos” on HBO. Texas was host to a similar reptile. Extra points if you can find it in our Triassic mural.

Late Triassic, New Jersey. A colony of vegetarian Hypsognathus emerges from its burrow. Maybe they had been hiding from podokesaurs. Maybe they had been watching Jersey favorite The Sopranos on HBO. Texas was host to a similar reptile. Extra points if you can find it in our Triassic mural.

Freshman year also introduced me to the tradition of the “mixer” — parties where Yalies and young women from nearby colleges co-mingled. At a Mt. Holyoke mixer, I got an earful from female geology students who were steamed, justifiably, about gender bias. Old fogey Yale profs grumbled that “girls can’t lift heavy rocks […] can’t do serious fossil work.” Podokesaurus was a counterargument. It was discovered in 1910 by none other than Dr. Mignon Talbot, who was chair of the geology department. Talbot did her Yale Ph.D. on sea-lilies, crinoids, relatives of starfish that were abundant in Devonian rocks of New York State (we have some fab Jurassic crinoids in our hall). Dr. Talbot went on to become president of the college.

The Wikipedia portrait of Dr. Talbot. The label must’ve been written by a Yale Professor.

The Wikipedia portrait of Dr. Talbot. The label must’ve been written by a Yale professor.

Even though, as college president, she out-ranked most of the Yale faculty of her time, they insisted on calling her “Miss Talbot instead ofDr. Talbot. Yeesh. In 1965, the Yale director of graduate studies told me “Bob, we shouldn’t give Ph.D.s to girls … they’ll just get married and have babies.” Double yeesh!

But he didn’t know how famous her dinosaur would yet become! Dr. Talbot’s dinosaur influenced Jurassic Park — yes, that little novel (series) turned super-franchise

In the article naming the beast, she noted that a similar-sized dino had just been excavated from the Late Triassic of Germany. It would be christened Procompsognathus” in belief that the renowned Compsognathus of the Late Jurassic might be a descendant (it isn’t). 

Since the one and only skeleton of the pro-compy is missing key parts, Dr. Talbot’s graceful Podokesaurus was used to fill in the blanks and give a general portrait of the fox-sized predators of the Late Triassic. Talbot’s creature gained more fame when it became the inspiration for an entire family, the Podokesauridae.

Later in the twentieth century more species were added to the podoke clan, including Coelophysis from New Mexico. The New York museums scored a mass grave of Coelophysis in the 1940s and 1950s: dozens of skeletons from adults two yards long to babies as small as Podokesaurus and Procompsognathus. 

Proud members of the Family Podokesauridae. Coeolphysis grew to seven feet long. Check out the pubis in these guys!!

Proud members of the Family Podokesauridae. Coeolphysis grew to seven feet long. Check out the pubis in these guys!

IMPORTANT WARNING! The Jurassic Park franchise uses two names for tiny Triassic dinos: “pro-compy” and “compy”. There might be confusion among the dino-laity.

The true Compsognathus is Late Jurassic, with kin in the Early Cretaceous, and it doesn’t have podoke family values. As we’ll see in a bit, Crichton clearly meant his tiny carnivores to be classic Late Triassic/Early Jurassic carnivores — and that means podokesaurs.

The podokes had a near-monopoly in the meat-eating role in the Late Triassic/Early Jurassic. They were not only small and mid-sized carnivores, equivalent to kit foxes, coyotes and wolves, but they became the movers and shakers in the apex predator role. Big species attained lengths of 22 feet and weights approaching a ton — bigger than the biggest land meat-eaters today (grizzly and polar bears). All podoke species had that graceful build of Dr. Talbot’s Podokesaurus: supple neck, long torso, and outstandingly elongated tail.

And, for those of you who are pelvis-literate, you’ll notice another design feature: The pubis bone was outstanding in the forward slant and length.

Podoke attack! A ten-foot long podokesaur predator menaces the thin-necked herbivore Anchisaurus. Early Jurassic, Massachussetts, somewhere near Amherst College. 

Podoke attack! A 10-foot long podokesaur predator menaces the thin-necked herbivore Anchisaurus. Early Jurassic, Massachussetts, somewhere near Amherst College.

For Jurassic Park fans, Procompsognathus rings a bell. In Michael Crichton’s novel, the first dino we get to know is tweensey (but deadly) — a species identified as a pro-compy. These blood-thirsty characters are fond of jumping into perambulators and biting the faces of juvenile humans. They move in gangs. Crichton was dead-on here. Tracks from the Triassic/Jurassic do document podoke-packs, small carnivores cavorting in groups.

Podoke dance floor? Slab of shale with a dozen small predators cavorting. 

Podoke dance floor? Slab of shale with a dozen small predators cavorting.

In the Jurassic Park movie, the pro-compys are unstoppable nasties who confront the gifted character actor, Wayne Knight (Newman) of Seinfeld fame. (Knight’s best known for portraying portly and disreputable men, but we should remember that he was a dashing romantic lead in Third Rock from the Sun.)

In Jurassic Park, Knight’s character learns a lesson — the hard way. At first, he insults the pro-compys and tries to scare them away. Then they flash their threat-collars, a device cribbed from the Australian Frilled-Lizard. Then they hurl loogies of what seems to be venomous schmaltz. Nice scene. Scary.

However, dino-nerds: watch out. There are no bones in the lizard collar so preservation in a skeleton would be unlikely. Plus, threat collars are unknown among the many dinos now represented by fossils with skin. 

Plus, plus, no dino could spit. Spitting requires complex lip and face muscles of the sort a trombonist must have (didja know I was first-trombonist in the school band?). Reptiles can’t spit, birds can’t spit. Fossil dino faces show that the big, complicated lips just weren’t there.

Spitting cobras cheat. They don’t really spit. They have mouth muscles that squeeze the poison gland so the venom comes squirting out through the hollow fangs. Clever, but not a genuine spit.

Crichton used his dinos carefully. He fills Jurassic Park and Lost World novels with a lovely time-safari through the Mesozoic. He begins with the pro-compy, from the earliest slice of dino-time, about 210 million years ago. The long-necked brachiosaurs and stegos filled out the later Jurassic, some 145 million years ago. You could add a true Compsognathus here if you like. For the Early Cretaceous, 110 million years ago, we are given Deinonychus antirrhopus (labeled Velociraptor but actually Deinonychus). Triceratops, T. rex and the advanced ostrich-dinos fill out the last slice of Cretaceous, the Lancian Age, 66 million years ago. You can teach an entire paleo course with this fine selection of fossils. 

Remember, in the books and movies the label “pro-compy” and “compy” is synonymous with the podokesaurs. Crichton did not intend his Triassic dino to be a Compsognathus, the Late Jurassic animal quite different in body plan from the podokesaurs. Here’s where dilophosaurs come in.

Dilophosaurus, sensu stricto, is a Southwest Early Jurassic apex meat-eater — a big brother of Coelophysis and Podokesaurus. The first specimens were announced by the Berkeley museum in the 1950s. Size: near maximum for the podoke family, nearly 2,000 pounds soaking wet. Our Chinese colleagues excavated a super diloph of the same body mass. In each and every bony bump, the dilophosaur is built to the same basic plan used for Coelophysis, et al. Big difference, besides size, is the side-by-side bone crests on the head.

The Berkeley diloph. Black-n-white foto shows first restoration of head without crests. Color snapshot shows the crests added. Michelangelo’s David in for scale. Do note that this is a biggish predatory dino. 

The Berkeley diloph. Black and white photo shows first restoration of head without crests. Color snapshot shows the crests added. Michelangelo’s David in for scale. Do note that this is a biggish predatory dino.

In the books, Crichton does not describe any head ornaments for his pro-compys. The movie, on the other hand, gives the little fellows side-by-side crests, perfect miniatures of what true dilophs have. I go to screenings of the JP franchise every chance I get (“JP” is what we insiders call Jurassic Park). When I saw the 3D version on the HMNS Giant Screen, I was treated to massive vibrations that punctuated the scary parts. 

“Dilophosaurus … DILOPHOSAURUS!” shouted the five-year-old sitting behind me. He was kicking the back of my seat with unconstrained enthusiasm. Can’t blame the kid. He had his plastic diloph in his lap, evidently a cherished pet and quite accurate in most anatomical details (neck and ankle too long, too skinny). The extreme close-ups of the pro-compy head on the screen did look diloph-y. But … the size was as wrong as wrong can be and still stay within the podoke family.

Plastic dilophosaur, by Safari Ltd. About nine bucks at the museum gift shop, with your member discount.

Plastic dilophosaur, by Safari Ltd. About $9 at the Museum Store, with your member discount.

I was tempted to turn around and issue a correction: “Hey kid, that dino is a hundred times too small …” But I restrained myself. I estimated that the leader of the movie pro-compy pack was no more than 15 pounds, Boston Terrier-sized. With head crests, size matters. Small podokes don’t have much in the way of cranial protuberances. All the big crests are on big heads attached to big bodies.

Want to be a podkesaur? You must get a nose-notch. Coelophysis here has one.

Want to be a podokesaur? You must get a nose-notch. Coelophysis here has one.

And … there was something more, something missing from the schnoz in the movie compy. “No nose notch …” I said to myself. “Those guys in the movie have no nose notch … so … they aren’t members of the Family Podokesauridae!”

Notches below the hole for the nostril are a big deal in dinos and dino-kin. Land Croc-oids of the Triassic, second cousins of dinosaurs, usually are notched. But strong notches are rare amongst the carnivorous dinosaurians. T. rex is notch-less. So is Allosaurus and all the myriad raptors, from Micro-raptor to Meso-raptor to Mega-raptor. The bona fide Compsognthus is notch-less. The podoke family is the most consistently notched. Enjoy my own diagram of the Harvard skull from Coelophysis above. Please stare at the nose. There’s a notch here. Dilophosaurus has an even more emphatic notch.

No notch = no podokesaurid. Simple as that.

What about that long, slanty pubis, another hallmark of the podoke family? Study the movie dino as long as you like. You will find no unambiguous evidence of long, slanty pubic bones. None.

My conclusion: the movie artists did a great job with the pro-compys. They cobbled together a frightening chimaera from a bunch of critters, some lizards, some small meat-eating dinos, some big ones. These little dinos are the most imaginative, most mixed-up of all the JP creations. So enjoy them! But you cannot use the movie pro-compys to teach a lesson in dilophosaurs or any dilophosaur kin. The movie “compy/pro-compy” is NOT a crested podokesaur.

* Recently, some paleontologists have insisted using the name Family Coelophysidae to replace Podokesauridae, because we have so many skeletons of Coelophysis. These folks are well-meaning but, ahem, I am a Yalie and so I am sworn to defend the honor of Mt. Holyoke College and all its faculty and graduates. And its presidents. And its dinosaurs.

The guts stop here: Delve deeper into dinosaurian intestines with Dr. Bakker

Attention all Dino-Nerds! Put Your Anatomical Expertise to Work. Prestigious Careers Await in the Field of Gastroenterology.*”

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Where the guts fit in a T. rex. The pubic bone (yellow) sticks down and won’t let the intestines expand behind the hip socket.

Often, I get approached by parents who fret over their dino-fixated kid. “You gotta help us, Doc. All she wants to do is read about fossils. Will she ever find a respectable career in the real world?”

I can reassure Mom and Dad that studying dino anatomy can lead to well-paid and honorable occupations — for instance, as a professor of anatomy or a foot surgeon or a knee specialist. Or a gastroenterologist. Being a gut doctor is becoming especially attractive now because aging yuppies are suffering from decades of intestinal abuse from spicy nachos and a misplaced reliance on gluten-free pizza.

So, adults, encourage the children to delve deeply into the dinosaurian intestines. It’s fun. It’s educational. It might pay off — big time.

T. rex was a gut-less wonder

The first step toward a visceral understanding of dinos is to face the fact that T. rex was a gut-less wonder. Consider the rexian body cavity. The space available for guts is severely limited. That’s because the intestines must stop at the pubic bone, the big prong that points straight down from the hip socket. It’s inviolable anatomical law: No intestines can be behind the pubis!

In a rex, that means all the guts are in front of the hip socket and there just isn’t a lot of room here. You might argue that rexes were forced to be pure carnivores because they needed high protein food that could be digested with a minimum weight of gastric equipment.

(Vegan advice: A gentle admonition to all my vegan friends in Boulder, Colorado: High fiber plant food demands big, complicated gut compartments, a series of vats where the fodder is soaked and softened, worked upon by microbes that secrete the enzymes needed to break down fiber. That explains why Herefords and zebras, which are consummate digesters of grass, have naturally rotund tummies. Contrary to widespread myths, we humans, when we first evolved, were not adapted to high fiber, animal-free diets. When Australopithecus evolved into our genus Homo, the size of the gut shrank dramatically. So we had to specialize in protein-rich food, such as eggs, baby birds, grubs, turtles, bunnies and antelope carcasses scavenged from unwary saber-tooth tigers — plus, of course, nutritious fruits and nuts and tasty tubers excavated with digging sticks and roasted over the fire. Fire was domesticated at about the time our guts diminished in volume. Cooking releases food value otherwise unobtainable with our small-size intestines. Today, a modern human can indeed survive on a plant-based diet but you choose your veggies carefully. And cook ‘em.)

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Fowl guts.

Chickens that don’t fall over

Now that we’ve learned the basic laws of gut size, we are ready to unlock the mystery of the balanced chicken. You’ll remember from the previous post that barnyard fowl have exquisite balance on just two legs, despite the lack of a heavy tail.

Here’s another fowl mystery: Chickens have formidable digestion. They can extract food value out of raw grains and plant fiber far better than we humans can. The secrets to balance and digestion are one in the same — the gut-wrenching development of the pubic bone. When an embryonic bird in its egg is just beginning to develop a pelvic skeleton, the pubis points down, sorta like an adult T. rex pubis does. But when the chick hatches, the pubis has rotated completely around so it points backward and the guts expand behind the thigh.

Brilliant! The pubic re-alignment has doubled the potential room for intestines. And all that new weight of intestines is behind the hips, and therefore, confers perfect balance without any sort of ponderous tail.

Pubic-wrenching is a splendid osteological trick. Some dinosaurs did exactly the same thing. Stroll past our fine duckbill skeletons. Fix your gaze on the pubic bone. It’s rotated backward, just like a four-ton version of the barnyard fowl.

The duckbills go even further in gut expansion than do most birds. The pubis and ischium (the other lower hip bones) are so extended toward the rear that the guts gain another yard or two of length and allow another couple of chambers for microbial action on the food. All those extra digestive vats would let the duckbill G.I. tract break down even the toughest, most fibrous vegetables.

Duckbills win the award for longest gut tract of any dinosaur. And, probably, had the least constipation problems.

There’s a word every dino-nerd learns in the first grade: “ornithischians”. The simple meaning is “dinos with bird-style hips,” and that denotes the many species, like duckbills, that have undergone gut-wrenching. Stegosaurs wrenched their pubes, as did Triceratops.

Make a game of it! Go through our Fossil Hall with the children seeing how many different skeletons show the backwardly-bent pubes. Make the whole family pubo-literate!

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Before and after gut-wrenching experience: Top duckbill dinosaur shows how intestines would be limited if the animal had the primitive, vertical pubis. Bottom duckbill shows the real bent-back pubis and ischium.

When I skulk around our tour guides as they talk to school groups, my rib cage swells with pride. Our docents are the best! So I want to add an advanced bit of pubic-lore here. Stegosaurs and many other gut-wrenched herbivores do something tricky, pubis-wise.

After they evolved the backward-pointing pubis, these dinosaurs grew new pubic prongs — one on each side of the rib cage — that pointed forward and outward. This new set of prongs didn’t change the gut layout at all. The new prong lies outside the body cavity. The guts lay between the left and right new prongs.

What good did the new prong do? A stout muscle probably attached to it and ran back to the thigh to help swing the hind leg forward. If your child is considering med school, tell her that this muscle is what we call in humans the “psoas.

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Colorado State dino, Stegosaurus, showing the new prong of the pubis that points forward. Don’t confuse it with the true pubis!

And now, the ultimate Darwinian inquiry into gut-wrenching, the question that earns me sour stares from all my creationist relatives (37 full cousins on one side, 97% creationists)…

Here’s the query: When did pubic-twisting happen in the evolution of birds?

The chicken diagram I used earlier works pretty good for all modern day birds — every single one of the 10,000 species. From hummingbirds to ostriches, today’s avian species have the strongly wrenched pubic shaft and the attendant elongation of all things intestinal. No modern bird has the vertical pubis and short gut of a T. rex.

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Diagram of Archaeopteryx from Heilmann’s 1926 book “Origin of Birds”, modified by me in 1958. Heilmann explained the mix of bird and pre-bird features.

Archaeopteryx surprises

When first discovered in the 1860s, the Late Jurassic Archaeopteryx was an evolutionary celebrity, a missing link combining perfectly formed avian designs with archaic dinosaurian features. The first “Archie” skeleton excavated was jumbled but it certainly looked like the long, thin pubic bone was bent back in standard bird configuration. “Archie” also possessed another definitive bird device — the lagoonal, limestone-preserved imprints of fully-formed flight feathers.

Some dino characteristics were retained too: sharp little teeth, curved claws on the fingers, separate bones in the wrist (modern birds fuse up the individual bony units), and a long bony tail. The Archie was dubbed “Ur-Vogel” in German, an event which solidified the critter’s place in nature.

“Proof that creationism is wrong and Darwin is right!” shouted many an agnostic in 1868. In fact, the chap who coined the term “agnostic,” Thomas Henry Huxley, led the charge in proclaiming birds as descendants of wee dinos. Huxley’s favorite dinosaurian was Compsognathus, the original “Chicken-Dino,” a Late Jurassic carnivore extracted from the very same lagoonal rock that produced Archaeopteryx.

The Compy skeleton was cute as a button — so small that Huxley could imagine it perched on his shoulder during debates about Darwinism. When I began reading dinosaur books in the 1950s, the Compy was still the tweensiest dino known and several kids’ stories had a pet Compy following a second grader to school.

That image was just too cutesy-pootsy, too Disney, and the Compsognathus needed a makeover to give the species gravitas. The Jurassic Park franchise of the 1980s did just that. In the first Jurassic Park book, Compys are turd-eating pack-hunters that would jump up into a crib in a children’s hospital to bite off the kid’s nose and cheeks and rest of the face. That scene definitely stripped away the excess cutesy.

In the movie Jurassic Park, the Compys were upgraded to frilled little monsters that spat narcotizing pea-soup in the face of characters before biting off their noses, cheeks and rest of their faces. That scene ripped away the excess pootsy.

Movie villains can seem especially evil when they begin as pint-sized plush toys and then metamorphose into killers. Remember Gremlins and Chucky? (Maybe the writers of Jurassic Park scripts were trying to do to Compys what Miley Cyrus did for herself — take an adorable little star and remake the image so it seems more adult and more formidable. I believe that, when you go slow-motion through the Jurassic Park movie, you can see some of the Compys twerking.)

(Be advised: Jurassic Park books and film mix and match parts from three different dinos: (1) The true Compsognathus, beloved of agnostics; (2) The enigmatic pro-compsognathids known only from incomplete Triassic specimens; and (3) The distant compy cousin, the hefty 20-footer, Dilophosaurus, from the Early Jurassic. None were poisonous. None could spit. But recent discoveries from China reveal a raptor with teeth grooved like a gila monster’s — that means poison glands dripped venom down the grooves into wounds. Cool.)

Bakker Dino Guts 6In all three real dinos that inspired the Jurassic Park Compys, the pubis pointed downward and forward, the primitive configuration for carnivorous dinos and retained in our Texas Coelophysis. No gut expansion here.

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Bambiraptor, a little raptor-type dinosaur from the Late Cretaceous. Diagram done for Dr. David Burnham and me when Bambiraptor was named. Note that the pubis is bent back just a bit.

In the 1970s, Yale’s John Ostrom rediscovered Huxley’s insights. He used the recently discovered Deinonychus and its kin to prove that raptor-type dinos had hands, feet and a tail nearly identical to what Archaeopteryx possessed. But raptors still had primitive pubic bones that were bent back just a little bit. See the raptor-pubes for yourself in our “Julie-raptor” skeleton on display at HMNS or in the Bambiraptor skeleton in the lab (come by and take a look).

So, because of its superior pubic wrenching, Archaeopteryx was entitled to be hailed as more advanced than most raptors.

That made us all happy because we could make a nifty evolutionary scenario — an early raptor-like dino, a Jurassic version of Deinonychus, evolved into an Archaeopteryx-oid and then the Archie-oid evolved into a modern bird in the Early Cretaceous. Take that, my creationist-cousins!

(By the way, don’t let TV’s South Park mislead you; the plural of “pubis” is “pubes,” and it’s pronounced “pew-bays” and not “pewbs.”)

But then came the inevitable Oops Moment. That happens whenever we get too cocky.

Our friends at the Thermopolis Dinosaur Center in central Wyoming announced they had obtained a near perfect Archaeopteryx in 2006. I rushed up to ogle it, armed with a zillion photos of all the other Archie specimens. I stared at the pubes.

The new specimen and the other best specimens showed that the simple pelvic scenario was wrong. The real, undistorted Archaeopteryx pubis pointed straight down. No backward wrenching at all. In other words, Archies had no gut expansion whatever. The Ur-Vogel was no more advanced in this one key hip feature than an allosaur or a tyrannosaur.

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A very accurate diagram of Archaeopteryx, drawn by the magisterial paleontologist Peter Wellnhofer, who is the all-time expert on Jurassic pterosaurs and birds. Note the disturbingly vertical pubis.

Dang, dang, double dang

In this one famous feature, the backward wrenching of the pubis, Archaeopteryx turns out to be less like a modern bird than Bambiraptor or Deinonychus. Gosh … nearly every ornithischian dinosaur has more advanced pubic positions than does an Archaeopteryx.

We should’ve known. Evolution hardly ever goes in a neat, straight line. The origin of birds didn’t come about as one undivided line of dinos that gets better and better, more and more like a chicken, from the Triassic through the Jurassic and then into the Cretaceous. Darwinian family trees are much more complicated and much more confusing — more like tangled blackberry bushes, full of short branches going off in all directions. There are side branches and side branches coming off the side branches.

Archaeopteryx itself couldn’t survive by being a mere ancestor; it had to fit into its local environment; it had to be adapted to its immediate surroundings. The short gut and un-wrenched pelvis worked fine. A cluster of raptor-like dinos, with minor variations in pubic slant, shared the basic Archaeopteryx blueprint — and they too thrived for millions of generations. Even in the latest part of the Cretaceous, un-wrenched guts with vertical pubes contributed to the success of little Bambiraptor type predators.

Finally, after the Cretaceous ended, all the raptor-type dinos and all the birds with vertical pubes were extinct. Now, in today’s habitats all over the world, no bird or bird-like animal operates with the un-wrenched gut. Why? Did the short gut prove inadequate somehow in the long run? Could be. But we must remember that short-gutted birds and raptor-like dinos had done very well since the Mid Jurassic to Late Cretaceous, and that’s a full 100 million years. It’s not totally true, the old adage, “No guts, no glory.”

* It’s traditional for paleontologists to teach anatomy to pre-meds. I did that for years: at Harvard, then at Johns Hopkins. Thomas Henry Huxley, who worked out relations between little dinos and birds in the 1860s, also taught courses in basic dissection. It’s even more socially acceptable to be a genuine medical doctor who also digs fossils.

True story, not a Seinfeld episode: When I visit my mom at the retirement home, she introduces me as “my son, Dr. Bakker.” All the octogenarian ladies lean forward smiling. Then, politely, they begin to ask specific questions about certain medical conditions. Mom whispers, “He’s not a real doctor…” and all the ladies lean back with a slight curl of disapproval in their smiles.

Nota bene: The new book Ten Thousand Birds, (Princeton University Press), is wicked good — best ever done on our feathered species. Beautifully written. Everyone should get a copy.