PROBAINOGNATHUS: FROM BITE TO SOUND

Among the towering dinosaurs, enormous marine reptiles and other spectacular fossils at the Natural History Museum Abu Dhabi is a much smaller creature that tells one of evolution’s most extraordinary stories.

It is a fossil of Probainognathus, a small, predatory cynodont from the Triassic Period of Argentina. At first glance, it is not especially imposing. 

It lacks the theatrical horns of Triceratops, the banquet-sized teeth of Tyrannosaurus rex and the general architectural confidence of a sauropod.

But look closely at its skull—particularly its jaw—and you are staring at a chapter in the evolutionary history of every mammal alive today.

That includes whales, bats, elephants, shrews, platypuses, cats, dogs and the primate currently reading this article.

Tiny creature. Enormous family consequences.

BEFORE THERE WERE MAMMALS

To understand Probainognathus, we need to travel back roughly 235 million years to the early part of the Late Triassic Period.

The world looked nothing like it does today. The continents were assembled into the supercontinent Pangaea. Dinosaurs had only recently appeared and had not yet become the dominant large animals of terrestrial ecosystems. 

Crocodile-line archosaurs, early dinosaur relatives, large amphibians and a wonderful assortment of synapsids occupied the land.

Synapsids are the great evolutionary lineage to which mammals belong. They diverged from the lineage leading to reptiles more than 300 million years ago. Although older books often describe many early synapsids as “mammal-like reptiles,” this is misleading. They were not reptiles slowly deciding to become mammals. Synapsids and reptiles were separate branches of the amniote family tree.

One branch eventually produced dinosaurs and birds. Another produced us.

Within the synapsids arose the therapsids, and within the therapsids evolved the cynodonts. The name Cynodontia means “dog teeth,” although most cynodonts would not have looked particularly dog-like. The name refers to features of their teeth and jaws rather than any secret Triassic ambition to become golden retrievers.

Cynodonts included animals ranging from sturdy plant-eaters to quick little predators. Over millions of years, members of this group developed many features associated with mammals: differentiated teeth, enlarged jaw muscles, changes in the palate, more efficient breathing, increasingly upright limbs and a lower jaw dominated by a single large bone called the dentary.

The evolutionary story did not unfold as a straight march from primitive to advanced. It was a branching, experimental process involving many species, most of which left no living descendants. Probainognathus belongs to one of the branches close to the part of the cynodont tree from which mammals eventually emerged.

It was not quite a mammal. It was certainly not our direct, neatly labelled great-great-grandparent. It was a non-mammalian cynodont whose anatomy preserves a revealing combination of older and more mammal-like features.

Evolution, as usual, was tinkering.

HONEY, I MADE A NEW FRIEND: MEET PROBAINOGNATHUS

The best-known species, Probainognathus jenseni, was formally named by American palaeontologist Alfred Sherwood Romer in 1970. Its fossils were collected from the Chañares Formation in La Rioja Province, northwestern Argentina.

The name Probainognathus is generally translated as “progressive jaw,” a direct reference to the feature that made the animal scientifically important. 

The species name honours fossil collector James A. Jensen, who led the team associated with the discovery of the original material.

Radiometric dating of volcanic minerals has placed the principal fossil-bearing interval of the Chañares Formation at approximately 236 to 234 million years old. The formation had previously been regarded as Middle Triassic, but more precise dating showed that much of its famous vertebrate assemblage belongs near the beginning of the Late Triassic.

At that time, what is now northwestern Argentina lay within a volcanically active rift basin. Rivers, lakes and floodplains supported an ecosystem filled with dicynodonts, cynodonts, early archosaur relatives and some of the animals living close to the origin of dinosaurs.

Volcanic ash and sediment repeatedly entered the landscape. In some areas, animals were buried within concretions—hard masses of mineral-rich rock that formed around their remains. These deposits preserved a remarkable record of Triassic terrestrial life, including animals that would otherwise have been very easy to overlook.

Probainognathus was small, lightly built and probably no more than about half a metre long, although complete skeletons are rare and estimates vary. Its skull was only several centimetres in length. It likely moved on four legs and probably hunted insects and other small animals, perhaps taking tiny vertebrates when the opportunity arose.

In other words, it was living through one of the most dramatic periods in vertebrate evolution while pursuing the equally urgent matter of finding something crunchy for dinner.

TEETH MADE FOR BUSINESS

The jaws of Probainognathus held differentiated teeth rather than a uniform row of nearly identical pegs.

At the front were small incisors. Behind them were enlarged canine teeth, followed by postcanine teeth adapted for processing food. Some specimens show serrations on the canines, suggesting that these teeth were useful for gripping and cutting flesh.

This regional specialization of the teeth—incisors for nipping, canines for piercing and postcanines for slicing or crushing—was an important development in cynodont evolution. Mammals would take this dental division of labour to remarkable extremes.

Think of the front teeth of a beaver, the canines of a wolf and the grinding molars of a horse. Each part of the tooth row performs a different job. Probainognathus did not possess the sophisticated chewing system of a modern mammal, but its teeth were already part of that broader evolutionary experiment.

Its skull also provided space for substantial jaw muscles. Changes in the skull and lower jaw allowed cynodonts to bite more effectively and process food more efficiently. That may have helped support higher levels of activity and, in later mammalian relatives, the energetic demands associated with endothermy.

Whether Probainognathus itself had fur or maintained a fully mammal-like body temperature cannot be established directly from its bones. Some cynodont relatives probably possessed whiskers or hair-like coverings, but soft tissues are rarely preserved. 

It is tempting to reconstruct Probainognathus as a fuzzy, bright-eyed little creature. That may be reasonable, but we should acknowledge where fossil evidence ends, and our fondness for adding whiskers begins.

THE JAW THAT CHANGED EVERYTHING

The real evolutionary celebrity in this fossil is the jaw joint.

Most non-mammalian jawed vertebrates use two small bones to connect the lower jaw to the skull. The quadrate bone in the skull meets the articular bone at the back of the lower jaw.

Living mammals do things differently. Our lower jaw consists almost entirely of one bone, the dentary, which articulates directly with the squamosal region of the skull. The old quadrate and articular bones no longer serve as the main jaw hinge.

They are now inside our ears.

Over the course of synapsid evolution, the quadrate became the incus, or anvil, while the articular became the malleus, or hammer. Together with the stapes, they form the three tiny middle-ear bones that transmit sound vibrations toward the inner ear.

Pause for a moment to admire the audacity of this arrangement. Bones that once helped an ancestor bite eventually became bones that help us hear.

No engineering committee proposed this reassignment. Evolution modified existing structures over many generations, gradually changing their size, position and function.

For this transition to occur, however, the lower jaw required a new way to attach securely to the skull. 

Several groups of advanced cynodonts developed additional contact between bones around the jaw joint while retaining the older quadrate–articular connection. For a time, these animals effectively possessed a transitional arrangement involving both the ancestral jaw hinge and a new secondary contact.

When Romer described Probainognathus, he interpreted its anatomy as showing an incipient articulation between the dentary and squamosal—the bones that form the mammalian jaw joint. This interpretation inspired the name “progressive jaw.”

Later studies have complicated that tidy picture. Some researchers concluded that the additional contact may have involved the surangular, one of the smaller bones behind the dentary, rather than a fully developed dentary–squamosal joint. 

More recent research has also shown that mammal-like jaw contacts arose independently in more than one cynodont lineage.

The route to the mammalian jaw was not a single anatomical escalator travelling smoothly upward. It was more like several teams attempting renovations at once, occasionally arriving at similar solutions.

Even with those scientific revisions, Probainognathus remains valuable. Its reduced postdentary bones, enlarged dentary and changing relationships among the bones at the back of the skull capture an important stage in the broader transformation of the cynodont jaw and ear.

It reminds us that transitional fossils are not required to be perfectly halfway between two modern categories. They document populations in which anatomical systems were being reorganized, often in complicated and unexpected combinations.

WHY BECOME SMALL?

Many of the cynodonts nearest the origin of mammals were small animals. Miniaturization may have played a major role in reshaping their skulls.

A smaller animal experiences different mechanical pressures. Its jaw bones become more delicate, its food may require precise processing, and hearing higher-frequency sounds can become increasingly useful. Small nocturnal or crepuscular hunters able to detect insects rustling through vegetation would have benefited from improved hearing.

At the same time, the dentary was becoming larger and stronger while the other bones of the lower jaw were shrinking. Once the new jaw articulation could bear the forces of biting, the old joint bones were increasingly free to specialize in transmitting sound.

The transition did not happen in one species or during one convenient evolutionary afternoon. Fossils record a prolonged series of changes. Some early mammaliaforms still retained connections between their middle-ear bones and the lower jaw. Complete separation occurred later and may have evolved independently in different mammalian groups.

Probainognathus stands near the beginning of this extraordinary anatomical story—not as the finished mammalian design, but as evidence that the old arrangement was already being altered.

A SMALL FOSSIL IN A VERY LARGE STORY

The Probainognathus fossil displayed at the Natural History Museum Abu Dhabi helps place mammals within the wider history of life. The museum’s exhibits carry visitors through billions of years of planetary change, and this unassuming cynodont earns its place among the giants.

Dinosaurs often dominate our vision of the Triassic and Jurassic worlds. They were large, spectacular and considerate enough to leave bones that look excellent in an atrium. Yet while dinosaurs were beginning their long reign, small cynodonts were undergoing an anatomical transformation that would ultimately produce the mammals.

Somewhere among their branches arose the earliest mammaliaforms. Their descendants survived the end-Triassic extinction, lived alongside the dinosaurs, endured the end-Cretaceous catastrophe and eventually diversified into nearly every terrestrial and marine environment on Earth.

The remarkable thing about Probainognathus is not that it was “almost us.” Evolution does not work toward a predetermined destination, and the creature certainly did not know that we would someday inspect its jaw for clues to the origin of the human ear.

It was simply a small predator trying to survive in Triassic Argentina.

But within its skull, old bones and new relationships had begun to overlap. A lower jaw built from several bones was moving toward one dominated by the dentary. An ancestral jaw joint was being joined by new contacts. 

Bones that still helped support feeding were entering an evolutionary process that would eventually place their descendants deep inside the mammalian middle ear.

The next time you chew while listening to someone speak, consider the two systems working on either side of your skull. One allows your dentary to move against the skull. The other uses three tiny bones to transmit the sound.

Their histories are intimately connected.

And part of that history can be seen in a modest little fossil in Abu Dhabi: Probainognathus, the progressive jaw that helped reveal how mammals learned to bite—and, eventually, to hear.

References and Further Reading

Romer, A. S. 1970. “The Chañares (Argentina) Triassic Reptile Fauna. VI. A Chiniquodontid Cynodont with an Incipient Squamosal-Dentary Jaw Articulation.” Breviora 344: 1–18.

Marsicano, C. A. et al. 2016. “The Precise Temporal Calibration of Dinosaur Origins.” Proceedings of the National Academy of Sciences 113: 509–513.

Martinelli, A. G., Soares, M. B. & Schwanke, C. 2016. “Two New Cynodonts from the Middle–Early Late Triassic of Brazil and Comments on South American Probainognathians.” PLOS ONE 11: e0162945.

Anthwal, N., Joshi, L. & Tucker, A. S. 2013. “Evolution of the Mammalian Middle Ear and Jaw: Adaptations and Novel Structures.” Journal of Anatomy 222: 147–160.

University of California Museum of Paleontology. Jaws to Ears in the Ancestors of Mammals.

Natural History Museum Abu Dhabi. Official Museum Website.

Lead Image: Asset id: 2757017209. Abu Dhabi UAE 8th Feb 2026: A Probainognathus fossil at the Natural History Museum Abu Dhabi reveals an early mammal-like cynodont, offering insight into the origins of mammals

AVES: LIVING DINOSAURS

Cassowary, Casuariiformes

Wherever you are in the world, it is likely that you know your local birds. True, you may call them des Oiseaux, pássaros or uccelli — but you'll know their common names by heart.

You will also likely know their sounds. The tweets, chirps, hoots and caws of the species living in your backyard.

Birds come in all shapes and sizes and their brethren blanket the globe. It is amazing to think that they all sprang from the same lineage given the sheer variety. 

If you picture them, we have such a variety on the planet — parrots, finches, wee hummingbirds, long-legged waterbirds, waddling penguins and showy toucans. 

But whether they are a gull, hawk, cuckoo, hornbill, potoo or albatross, they are all cousins in the warm-blooded vertebrate class Aves. 

The defining features of the Aves are feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. The best features, their ability to dance, bounce and sing, are not listed, but it is how I see them in the world.

These modern dinosaurs live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. 

There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds.

Wings evolved from forelimbs giving birds the ability to fly

Wings, which evolved from forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. 

The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming.

Wee Feathered Theropod Dinosaurs

We now know from fossil and biological evidence that birds are a specialized subgroup of theropod dinosaurs, and more specifically, they are members of Maniraptora, a group of theropods that includes dromaeosaurs and oviraptorids, amongst others. As palaeontologists discover more theropods closely related to birds, the previously clear distinction between non-birds and birds has become a bit muddy.

Recent discoveries in the Liaoning Province of northeast China, which include many small theropod feathered dinosaurs — and some excellent arty reproductions — contribute to this ambiguity. 

Still, other fossil specimens found here shed a light on the evolution of Aves. Confuciusornis sanctus, an Early Cretaceous bird from the Yixian and Jiufotang Formations of China is the oldest known bird to have a beak.

Like modern birds, Confuciusornis had a toothless beak, but close relatives of modern birds such as Hesperornis and Ichthyornis were toothed, telling us that the loss of teeth occurred convergently in Confuciusornis and living birds.

The consensus view in contemporary palaeontology is that the flying theropods, or avialans, are the closest relatives of the deinonychosaurs, which include dromaeosaurids and troodontids.

Together, these form a group called Paraves. Some basal members of this group, such as Microraptor, have features that may have enabled them to glide or fly. 

The most basal deinonychosaurs were wee little things. This raises the possibility that the ancestor of all paravians may have been arboreal, have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, tummy contents from recent avialan studies suggest that the first avialans were omnivores. Even more intriguing...

Avialae, which translates to bird wings, are a clade of flying dinosaurs containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to modern birds — Aves — than to deinonychosaurs, though alternative definitions are occasionally bantered back and forth.

The Earliest Avialan: Archaeopteryx lithographica

Archaeopteryx, bird-like dinosaur from the Late Jurassic

Archaeopteryx lithographica, from the late Jurassic Period Solnhofen Formation of Germany, is the earliest known avialan that may have had the capability of powered flight. 

However, several older avialans are known from the Late Jurassic Tiaojishan Formation of China, dating to about 160 million years ago.

The Late Jurassic Archaeopteryx is well-known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. 

Archaeopteryx was the first fossil to clearly display both traditional reptilian characteristics — teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor.

Unlikely yet true, the closest living relatives of birds are the crocodilians. Birds are descendants of the primitive avialans — whose members include Archaeopteryx — which first appeared about 160 million years ago in China.

DNA evidence tells us that modern birds — Neornithes — evolved in the Middle to Late Cretaceous, and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 mya, which killed off the pterosaurs and all non-avian dinosaurs.

In birds, the brain, especially the telencephalon, is remarkably developed, both in relative volume and complexity. Unlike most early‐branching sauropsids, the adults of birds and other archosaurs have a well‐ossified neurocranium. In contrast to most of their reptilian relatives, but similar to what we see in mammals, bird brains fit closely to the endocranial cavity so that major external features are reflected in the endocasts. What you see on the inside is what you see on the outside.

This makes birds an excellent group for palaeoneurological investigations. The first observation of the brain in a long‐extinct bird was made in the first quarter of the 19th century. However, it was not until the 2000s and the application of modern imaging technologies that avian palaeoneurology really took off.

Understanding how the mode of life is reflected in the external morphology of the brains of birds is but one of several future directions in which avian palaeoneurological research may extend.

Although the number of fossil specimens suitable for palaeoneurological explorations is considerably smaller in birds than in mammals and will very likely remain so, the coming years will certainly witness a momentous strengthening of this rapidly growing field of research at the overlap between ornithology, palaeontology, evolutionary biology and the neurosciences.

Reference: Cau, Andrea; Brougham, Tom; Naish, Darren (2015). "The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): Dromaeosaurid or flightless bird?". PeerJ. 3: e1032. doi:10.7717/peerj.1032. PMC 4476167. PMID 26157616.

Reference: Ivanov, M., Hrdlickova, S. & Gregorova, R. (2001) The Complete Encyclopedia of Fossils. Rebo Publishers, Netherlands. p. 312.

DINOSAUR RIVALRY: MANTELLISAURUS

Mantellisaurus atherfieldensis 

This story begins some 125 million years ago on the lush floodplains of what is now the Isle of Wight, back in the Cretaceous.

Forget the cool, windswept English coastline of today. This was a warm, subtropical world of broad rivers, oxbow lakes and sprawling wetlands, where towering conifers, cycads and tree ferns sheltered one of Europe's richest dinosaur ecosystems. 

Early flowering plants were just beginning to appear, while insects buzzed through the forests and reptiles called across the floodplains.

Here, herds of Mantellisaurus atherfieldensis browsed on tender vegetation. At seven to eight metres (23–26 feet) long, these elegant herbivores were among the largest animals in their world. 

Their long hind limbs suggest they could move surprisingly quickly when needed—particularly if a hungry Neovenator emerged from the trees. 

Nothing encourages cardio quite like becoming someone else's lunch.

Its hands were every bit as remarkable as the rest of the animal. Projecting from each was a formidable thumb spike. Victorian artists loved depicting these dinosaurs charging into battle like armoured knights, but the reality was likely less theatrical. 

The spikes probably served as defensive weapons, may have helped settle disputes during the breeding season and perhaps even assisted in pulling down stubborn vegetation. Evolution has always appreciated a multitool.

The elongated fifth finger tells another story. Unlike the stout thumb, it was surprisingly flexible, capable of curling around branches to draw foliage closer—a wonderfully delicate adaptation for an animal weighing well over a tonne.

This specimen was discovered in 1914 by geologist Reginald Walter Hooley in the Upper Vectis Formation near Atherfield on the Isle of Wight. 

Described in 1917 and formally named Iguanodon atherfieldensis in 1925, it spent more than eighty years as a member of the ever-growing Iguanodon family.

That changed in 2007, when American palaeoartist and researcher Gregory S. Paul recognised that it was something quite different. 

More lightly built, with longer limbs and closer evolutionary ties to the African iguanodontian Ouranosaurus, it deserved a genus of its own. Paul named it Mantellisaurus, honouring Dr Gideon Algernon Mantell, the Sussex physician whose discoveries helped launch the science of dinosaurs.

Mantell's story is one of brilliance, perseverance and one of Victorian science's greatest rivalries.

In 1822, he described Iguanodon, only the second dinosaur ever scientifically named.

Mantell spent decades collecting fossils and championing these extraordinary animals, only to find himself increasingly at odds with the formidable anatomist Sir Richard Owen.

Owen coined the word Dinosauria and later became the driving force behind London's Natural History Museum, but he also had a habit of eclipsing rivals—and few felt that more keenly than Mantell. The two men disagreed about almost everything, from dinosaur anatomy to broader questions of evolution, as they emerged in Victorian science.

Mantell increasingly recognised that these animals were active, lightly built and far more dynamic than giant lizards. Owen preferred to reconstruct them as slow, heavily built, rhinoceros-like reptiles that fit comfortably within his creationist view of nature.

When Benjamin Waterhouse Hawkins created the famous Crystal Palace dinosaurs during the 1850s, it was Owen's interpretation that guided the sculptures. 

Visitors marvelled at enormous reptilian beasts, including an Iguanodon sporting what appeared to be a horn proudly perched upon its nose.

As science advanced—and as more complete skeletons were discovered, particularly the spectacular Bernissart specimens from Belgium—we learned that the famous "horn" was, in fact, the thumb spike.

One of the most iconic mistakes in palaeontology had become one of its best-known corrections.

FEATHERED SHOW-OFF OF THE CRETACEOUS: OVIRAPTOR

If ever there were a dinosaur that looked like it had dressed for a gala while everyone else showed up in sensible hiking boots, it was Oviraptor.

Picture yourself standing on the warm floodplains of Mongolia some 75 million years ago. The air shimmers with heat. 

Ferns rustle gently in the breeze. Somewhere nearby, insects hum while distant hadrosaurs grumble to one another. 

Then, stepping lightly between low shrubs, comes a creature unlike almost any other dinosaur.

About the size of a large turkey—though with considerably better posture—Oviraptor carries itself with quiet confidence. 

Its toothless beak gleams in the sunlight, its elegant neck curves gracefully, and atop its head rises a tall, bony crest that seems almost purpose-built for showing off. 

Draped across its body are feathers that catch the light with flashes of bronze, emerald, copper and midnight blue, colours that shift with every movement. 

Much like the iridescent plumage of today's magpies, starlings and peacocks, those shimmering feathers may have dazzled rivals and potential mates alike.

It is difficult not to smile looking at this wonderful oddball. Despite its fearsome name—Oviraptor means "egg thief"—it has spent more than a century trying to clear its reputation.

The first Oviraptor fossils were discovered in 1923 during the American Museum of Natural History's legendary Central Asiatic Expeditions to the Gobi Desert of Mongolia, led by the adventurous Roy Chapman Andrews. 

At the spectacular fossil beds of Bayn Dzak—the famous Flaming Cliffs—the expedition uncovered a partial skeleton lying beside a clutch of fossil eggs. It was a sensational find.

Henry Fairfield Osborn formally described the animal in 1924, naming it Oviraptor philoceratops—"egg thief, lover of ceratopsian eggs." 

We believed for many years that the dinosaur had been caught red-handed, stealing the eggs of Protoceratops. It made for a wonderfully dramatic story.

There was just one small problem. The story was wrong.

Decades later, beautifully preserved embryos discovered inside similar eggs revealed that they belonged not to Protoceratops, but to Oviraptor and its close relatives. 

Even more extraordinary were fossils of adults preserved sitting over their nests with their feathered forelimbs spread protectively around their eggs, as many modern birds do today. 

Rather than a notorious nest robber, Oviraptor appears to have been an exceptionally devoted parent that likely died defending its own young during a sudden sandstorm. While this all played out millions of years ago, it still pulls at my heartstrings. 

Talk about a public relations disaster. If dinosaurs had lawyers, Oviraptor would almost certainly have won its defamation case.

Those remarkable fossils revealed something else just as exciting. Adults carefully brooded their nests with feathered arms extended over the eggs, insulating them while allowing air to circulate. It is a strategy remarkably similar to that used by many birds today and a beautiful reminder that some of the most familiar behaviours in our backyards have roots deep in the Age of Dinosaurs.

Oviraptor belonged to a remarkable group of feathered theropods called oviraptorosaurs. These animals shared a common ancestor with the lineage that ultimately gave rise to modern birds. While Oviraptor itself was not a direct ancestor of living birds, it sits close to that evolutionary branch, preserving many features we now think of as unmistakably avian.

Its lightweight skeleton, hollow bones, wishbone (furcula), feathers, bird-like wrists and remarkable nesting behaviour all tell the story of dinosaurs becoming birds—not in one dramatic leap, but through millions upon millions of years of evolutionary refinement.

Its beak was another clever adaptation. Rather than relying on rows of sharp teeth, Oviraptor likely used its powerful jaws to crack open nuts, seeds, shellfish and other tough foods. It probably sampled the occasional egg when opportunity presented itself—as plenty of modern birds do—but certainly not often enough to deserve becoming prehistory's most infamous "egg thief."

And that magnificent crest? It was almost certainly less about battle than beauty.

Think of it as the Late Cretaceous equivalent of an extravagant hairstyle. Like the casque of a cassowary or the elaborate adornments of hornbills, the crest probably helped attract mates, establish dominance and identify individuals. Nature, it seems, has always had a flair for dramatic fashion.

Many of the behaviours we delight in watching among birds today—displaying, nesting, brooding, caring for young—were already well established while Tyrannosaurus still ruled the landscape.

Every new feathered dinosaur we uncover paints a picture of the Late Cretaceous as a landscape alive with colour, courtship displays, parental devotion and astonishing diversity. 

Flashing feathers shimmered in the sunlight. Elaborate dances played out across ancient floodplains. Tender parents guarded carefully tended nests while giant predators stalked the horizon.

Their descendants bring me joy each morning as I enjoy my first coffee of the day listening to their hoots and calls. The dinosaurs never truly disappeared. Some simply traded thunderous footsteps for morning birdsong.

Fossil Oviraptor Image: Danny Ye, License: 2765957049

LURKING IN THE LATE CRETACEOUS: RAJASAURUS

Rajasaurus narmadensis

In the humid, fern-thick forests of Late Cretaceous India — about 67 million years ago — a flash of red moves between the tree trunks.

Think oxidized iron and dried blood — deep crimson-orange broken by pale white striping and bold black bands along the flanks and tail. 

In dappled forest light, those stripes would fracture the animal’s outline, a trick modern tigers use to unnerving effect. Camouflage is not new. Evolution figured that out long before mammals started prowling.

This is Rajasaurus narmadensis, the “king lizard of the Narmada,” known from the Lameta Formation of central India. 

At roughly 6–7 meters long and weighing perhaps a metric ton, it was not the largest theropod of its time — but it did not need to be. It was built for hunting.

Rajasaurus belongs to the Abelisauridae, a clade of short-snouted, deep-skulled theropods that dominated the southern continents of Gondwana. If you squint, you can see its relatives in Madagascar’s Majungasaurus, Argentina’s Carnotaurus, and Africa’s Rugops. These animals were the southern answer to the tyrannosaurs of the north.

Unlike the long-snouted, banana-toothed elegance of Tyrannosaurus rex, abelisaurids had blunt, boxy skulls and often elaborate cranial ornamentation. Rajasaurus sported a single low horn or dome on its forehead — not a unicorn spike, but a thickened bony crest. 

It likely served for display, species recognition, or perhaps ritualized head-shoving contests. Theropods were dramatic. This is not speculation; this is pattern recognition across deep time.

Its forelimbs? Tiny. Comically so. Abelisaurids doubled down on arm reduction — evolution looked at the T. rex blueprint and said, “Let’s go smaller.” The arms were functionally irrelevant in prey capture. This was a head-driven predator. And what a head it was.

Rajasaurus lived in interesting times. Late Cretaceous India was not yet welded to Asia. It was a drifting island continent, sliding northward across the Tethys Ocean. The climate was warm, seasonally dry, punctuated by monsoonal rains. River systems braided across floodplains. Forests of conifers, palms, and flowering plants thickened along waterways. Ferns and horsetails crowded the understory.

Sharing that forest were enormous titanosaurian sauropods, including forms like Isisaurus and Jainosaurus. Long-necked, barrel-bodied giants moved in herds, stripping vegetation and reshaping the landscape as they fed. Their hatchlings and juveniles would have been very much on Rajasaurus’s radar.

Small ornithischian dinosaurs darted through the brush. Crocodyliforms basked along muddy riverbanks. Turtles paddled in oxbow lakes. Mammals — small, mostly nocturnal insectivores — kept wisely out of sight.

Pterosaurs likely wheeled overhead. Insects buzzed. The forest was noisy, layered, alive.

And somewhere within it, Rajasaurus was listening.

Abelisaurids had thick necks and reinforced skulls. Biomechanical studies of relatives like Majungasaurus suggest a predatory style focused less on bone-crushing bite force and more on repeated, slashing bites combined with powerful neck musculature. Think controlled violence rather than single catastrophic impact.

Rajasaurus likely relied on ambush. In dense forest cover, speed over short distances would matter more than marathon endurance. Its hind limbs were strong and proportioned for bursts of acceleration.

Picture it waiting — body low, tail held rigid for balance. A subadult titanosaur lingers near the herd’s edge. A misstep. A moment of distraction. The red-and-white predator explodes from cover.

The jaws close around soft tissue — flank, neck, perhaps hind limb — and then release. Another strike. And another. Blood loss and shock do the rest. Abelisaurids may not have grappled like dromaeosaurs or crushed like tyrannosaurs, but they were efficient.

And they were persistent.

There is even evidence of cannibalism among some abelisaurids (looking at you, Majungasaurus), so it’s not unreasonable to suspect Rajasaurus would not waste protein when opportunity presented itself. 

The predators of the Late Cretaceous were not sentimental.

Phylogenetically, Rajasaurus sits within Abelisaurinae, closely related to Majungasaurus of Madagascar and South American forms such as Carnotaurus sastrei. This distribution tells a broader tectonic story — these predators evolved across the southern fragments of Gondwana before continental breakup isolated their lineages.

India’s northward drift preserved a snapshot of this southern evolutionary experiment just before the asteroid impact that would end the non-avian dinosaurs.

Rajasaurus lived within a few million years of that event. Which means this red-striped hunter walked forests that would soon vanish under global firestorms, impact winter, and ecological collapse.

The gorgeous illustration you see here is by the supremely talented Daniel Eskridge, licensed for use. Appreciate you, Daniel. 

Timing, as ever, is everything.

TERROR IN THE EARLY CRETACEOUS: SUCHOMIMUS

Here is a fellow to strike terror into your heart. 

Meet Suchomimus tenerensis, a large, long-snouted spinosaurid theropod who prowled what is now Niger during the Early Cretaceous, roughly 125 million years ago. 

If you imagine a T. rex that fell headfirst into a river ecosystem and decided fish were the future, you’re getting close. 

This was no blunt-faced bone-crusher. Suchomimus had a narrow, crocodile-like snout lined with over a hundred slender, conical teeth perfectly suited for gripping slippery prey.

The fossils we find from this terrifying fellow come primarily from the Elrhaz Formation in the Ténéré Desert of the Sahara. 

Today, it is an expanse of sand and heat shimmer. In the Early Cretaceous, it was a lush floodplain threaded with rivers, swamps, and seasonal lakes. Think mangroves, ferns, and conifers rather than dunes. Fossil remains of Suchomimus were first discovered in the 1990s by a team led by Paul Sereno, and its name fittingly means “crocodile mimic.”

Suchomimus shared this watery paradise with a lively cast of characters. The sail-backed Ouranosaurus browsed on vegetation nearby. 

The stocky, heavily armored Nigersaurus grazed low-growing plants with its astonishing vacuum-cleaner jaw. Small, nimble theropods darted through the undergrowth. And lurking in the water were giant crocodyliforms like Sarcosuchus imperator, the so-called “SuperCroc,” who could grow over 11 metres long. Imagine the tension at the riverbank. You go fishing and something bigger than your canoe is watching you fish.

Diet-wise, Suchomimus was likely a specialized piscivore, meaning fish were firmly on the menu. Its long jaws, studded with conical teeth and a subtle rosette at the tip, were built for snapping shut on struggling prey. The teeth lack the serrations you see in typical meat-slicing theropods, suggesting it wasn’t primarily designed for tearing chunks from large dinosaurs. 

That said, it was still a 10–11 metre predator with powerful forelimbs and a thumb claw that could make an impression. Fish may have been the specialty, but opportunism is practically a dinosaur hobby. Small terrestrial prey would not have been safe if they wandered too close.

Hunting probably involved a patient, semi-aquatic strategy. Its long snout allowed it to dip into shallow water with minimal disturbance, and the conical teeth helped trap wriggling fish. 

Some spinosaurids show evidence of sensory pits in their snouts, similar to modern crocodilians, suggesting they could detect movement in water. While direct evidence for this in Suchomimus is still debated, the resemblance is striking enough to make you wonder whether it had a similar trick up its sleeve. Or, more accurately, up its snout.

Unlike its later and more extreme cousin Spinosaurus, Suchomimus does not appear to have had a towering sail. Instead, it sported a low ridge of elongated neural spines along its back, perhaps forming a modest hump or ridge. Stylish, but not showy. Think understated riverbank chic.

One of the fun quirks of Suchomimus is its place in the spinosaurid family tree. It sits in the Baryonychinae, closely related to Baryonyx from England. Yes, England. So while one cousin stalked Early Cretaceous river systems in what is now West Africa, another was doing much the same in Surrey. 

Spinosaurids, it seems, were cosmopolitan anglers.

And then there are those arms. Strong, well-developed forelimbs with large claws, including a prominent thumb claw, suggest it could grapple with prey or perhaps haul itself along muddy banks. It was not the tiny-armed stereotype of later theropods. 

If Suchomimus reached out to grab something, it likely succeeded.

In the fossil record, Suchomimus helps us understand the early evolution of spinosaurids before they became even more specialized. It represents a moment when dinosaurs were experimenting with ecological niches beyond the classic terrestrial predator role. We think of river margins as classic crocodile territory. Think again. They were contested real estate.

So picture it: 125 million years ago, on a warm Cretaceous floodplain in what is now the Sahara, a long-snouted predator stands at the water’s edge. 

Fish scatter beneath the surface. A distant Ouranosaurus snorts. Somewhere, a SuperCroc slides silently into the river. 

And Suchomimus waits, patient and perfectly adapted, the elegant angler of the dinosaur world. Not every theropod needed to rule the land. Some were quite happy ruling the river.

DINOSAUR RIDGE: DENVER, COLORADO

Tucked along the Front Range of the Rocky Mountains, just outside Denver, Colorado, lies one of the world’s most famous fossil localities: Dinosaur Ridge. 

This epic landscape is a place where deep time is etched into stone, where dinosaurs left their mark 150 million years ago, and where modern visitors can step directly into prehistory. It is a little like heaven!

The ridge is part of the Morrison Formation, a Late Jurassic rock unit renowned for its abundance of dinosaur fossils. Many of the first specimens that shaped our understanding of North American dinosaurs—including Stegosaurus, Apatosaurus, Diplodocus, and Allosaurus—were discovered here in the late 1800s during the feverish days of the Bone Wars — the famous fossil hunting fighting days of Cope and Marsh. 

Today, Dinosaur Ridge serves as both an outdoor museum and a natural classroom, where geology and paleontology meet fresh mountain air.

The main attraction is the Dinosaur Ridge Trail, a 1.5-mile paved walk (shuttle service is also available). Along the way, interpretive signs and viewing points highlight the ridge’s fossil treasures:

• Dinosaur tracks: Hundreds of fossilized footprints line the sandstone, most famously those of Iguanodon-like ornithopods and fearsome carnivorous theropods. Standing where a dinosaur once strode is both humbling and exhilarating.
• Ripple marks and mud cracks: These ancient impressions show that the area was once a shallow shoreline, where dinosaurs waded and water receded, leaving behind patterns still visible millions of years later.
• Bone quarries: Exposed rock layers reveal the same fossil-rich beds where early paleontologists extracted bones of long-necked sauropods and armored Stegosaurus.

The site also features striking geology, with tilted rock layers rising dramatically at an angle, giving visitors a clear glimpse into Earth’s shifting crust.

The Visitor Center Experience

Before or after the trail, the Dinosaur Ridge Visitor Center is worth a stop. Inside, you’ll find fossil replicas, hands-on activities for kids, and exhibits that tell the story of the dinosaurs and the scientists who first uncovered them. The staff and volunteers—many of them seasoned interpreters—bring the ridge’s history to life with enthusiasm.

What It Feels Like to Be There

Visiting Dinosaur Ridge gives all the "feels" you could ever ask for in a paleo field trip. The air is filled with the mingled scent of sagebrush and sun-warmed stone, while meadowlarks call from the surrounding grasslands. Standing beside a line of fossilized tracks, you can almost hear the splash of giant feet in mud, the rustle of prehistoric vegetation, and the low rumble of sauropods moving in herds. 

The contrast between Denver’s skyline in the distance and the Jurassic world beneath your feet makes for a surreal and unforgettable moment.

Planning Your Visit

• Location: Just off C-470 near Morrison, Colorado, about 25 minutes from downtown Denver.
• Best time to go: Spring and fall for cooler weather, though summer mornings can be pleasant.
• Accessibility: The paved trail is walkable, with shuttles available for those who prefer not to hike.
• Events: Check the Dinosaur Ridge website for guided tours, fossil festivals, and kids’ programs.

To stand on those rocks is to place yourself in a continuum of discovery, from the dinosaurs themselves, to the fossil hunters of the 19th century, to today’s scientists still uncovering new secrets. 

Whether you’re a lifelong paleontology fan or just curious about Earth’s story, Dinosaur Ridge offers a rare chance to literally walk in the footsteps of giants.

BULL CANYON DINOSAUR TRACKSIDE OF EASTERN UTAH

Darrin Mottler's Human to Theropod Comparison

The wind always arrives first.

It sweeps across the red cliffs of eastern Utah, brushing your shoulders like a quiet invitation as you step out onto the stone. 

The La Sal Mountains rise blue and snow-dusted on the horizon—silent, ancient witnesses. 

At your feet, the sandstone is warm, sun-baked, and patterned with bowls and dimples that look, at first, like the aftermath of a rainstorm.

But then you kneel.

You place your hand inside one of the indentations—fingers spreading to follow the outline—and suddenly time collapses. 

Your palm disappears into a footprint three times the size of your own, pressed into this rock nearly 190 million years ago by a three-toed dinosaur striding across a muddy lakeshore. 

The warmth of the desert stone meets your fingers and presses against the cool, deep sensation of time.

This is Bull Canyon Tracksite, one of Utah’s most awe-inspiring windows into the Jurassic.

Bull Canyon lies on the western flank of the La Sal Mountains, within a rugged plateau of red Wingate and Navajo sandstone. The site preserves an astonishing spread of footprints left by Early Jurassic theropods—light, agile, meat-eating dinosaurs with talons and hollow bones, the forerunners of modern birds.

Dinosaur Track, Bull Canyon, Utah

The tracks rest within the Glen Canyon Group formations, sediments laid down along the shifting margins of a prehistoric playa lake system. 

Here, mudflats dried and cracked under the sun, then were wetted again by brief storms—an ideal condition for holding tracks long enough to be buried by the next layer of sand.

Among the most distinctive ichnotaxa present are:

• Grallator – small, delicate three-toed prints often linked to slender theropods.
• Eubrontes – larger, deeper, more robust prints associated with big-bodied carnivores like Dilophosaurus.
• Occasional ornithischian tracks, including possible Anomoepus prints, representing small herbivorous dinosaurs moving across the same shoreline.

Dinosaur Track, Bull Canyon, Utah

Standing before them, the sandstone seems alive with movement. Each footprint shows a frozen splash of action: the slip of a claw, the twist of a heel, the moment a predator shifted its weight.

Every print reveals insights. Some trackways show animals striding with long, confident steps—suggesting a loping, ground-covering gait. Others are tight and compact, indicating slower or more cautious movement.

Parallel trackways record two or more animals moving in the same direction at the same time—possible group travel, or predators trailing prey.

A few prints deform the underlying sediment, proof that the ground was saturated with water. Others preserve delicate claw tips, showing firmer, drying mud. These shifts map out rapid climate cycles in Early Jurassic Utah.

It’s a moment-by-moment account of life—written in the most ephemeral of materials. 

So why does eastern Utah have so many dinosaur tracks? The region around Moab and the La Sal foothills is a world-class dinosaur track corridor with many elements at play.

• Jurassic climate: alternating wet and dry periods created perfect track-preservation conditions.
• Basins & playas: low-lying flats captured footprints from multiple dinosaur species.
• Rapid burial: shifting dunes and lake sediments quickly sealed impressions.
• Erosion today: modern uplift and weathering have brought these ancient surfaces back to light.

Bull Canyon is one of the most accessible of the sites, offering broad paleosurface exposures ideal for study and public viewing. If you visit at sunrise, the low light throws shadows into the footprints. The tracks seem to deepen, their edges turning crisp like the outline of a freshly pressed print. 

Photo Credit: All photos shown here are by the deeply awesome Darrin Mottler, who generously shared them with me and introduced me to the site. Appreciate you, Darrin!

TOROSAURUS: FRILLS, BROW AND HORNS

Torosaurus was a ceratopsian dinosaur that lived during the Cretaceous. These fellows look very similar to their Triceratops cousins but are an entirely different species in their own right. 

In 1891, two years after the naming of Triceratops, a pair of ceratopsian skulls with elongated frills bearing holes were found in southeastern Wyoming, Niobrara County, by John Bell Hatcher. 

Hatcher's employer, palaeontologist Professor Othniel Charles Marsh, coined the genus Torosaurus for them. While an estimated 2,000 Triceratops specimens have been collected from the American West, only seven partial skulls of Torosaurus have been found, so they are pretty rare.

Like Triceratops, they had massive skulls. Torosaurus had one of the largest skulls of any known land animal, with the frilled skull reaching 2.77 metres (9.1 ft) in length. Torosaurus were about the same size as Triceratops. 

They had an elongated frill with large openings (fenestrae), long squamosal bones of the frill with a trough on their upper surface, and the presence of five or more pairs of hornlets (epoccipitals) on the back of the frill. Torosaurus also lacked the long nose horn seen in Triceratops prorsus, and instead resembled the earlier and more basal Triceratops horridus in having a short nose horn. Three species have been named, Torosaurus latus, T. gladius and T. utahensis. T. gladius is no longer considered a valid species.

Wyoming Outcrops

The individuals referred to as Torosaurus are all large, comparable to the largest Triceratops specimens. Due to the elongated frill, especially the skull length is considerable. Hatcher estimated the skull of YPM 1830 at 2.2 metres, and of YPM 1831 at 2.35 metres. 

In 1933, Richard Swann Lull increased this to 2.4 metres and 2.57 metres respectively. Based on this, Torosaurus was thought, albeit briefly, to have the longest skull of any known land animal. 

Sixty-five years later in 1998, Thomas Lehman claimed that a Pentaceratops specimen possessed a partial skull that would have been 2.9 metres long in life. This was again doubted by Nicholas Longrich who in 2011 named this exemplar as a separate genus Titanoceratops and concluded its skull had been reconstructed as too long.

In 2006, Andrew Farke, a palaeontologist at the Alf Museum of Paleontology in South Dakota, pointed out that the new skulls described by him were on average even longer than Hatcher's original two: MOR 1122 has a length of 252 centimetres and MOR 981 of 277 centimetres.

Farke’s research interests focus on exploring the Cretaceous continental ecosystems of North America, particularly the ceratopsian (horned) dinosaurs, with active fieldwork in California and Wyoming.

In 2006, Farke published some diagnostic traits of Torosaurus. The frill is extremely long in comparison to the remainder of the skull. The rear, parietal, and edge of the frill bear ten or more epiparietals, triangular osteoderms. A midline epiparietal is absent; likewise, no osteoderm straddles the parietal-squamosal boundary. The parietal bone is thin. It is pierced by parietal fenestrae in the form of circular or transversely oval openings. The parietal bone is about 20% wider than long. 

Farke also identified a single trait in which T. latus differed from both Triceratops horridus and T. utahensis: its squamosal bore a conspicuous ridge on the edge with the parietal combined with a deep longitudinal trough parallel to it.

Farke pointed out that the known Torosaurus specimens are rather variable. The orbital "brow" horns are sometimes large and curved to the front, as with MOR 981, and sometimes short and straight as shown by MOR 1122 and ANSP 15191. 

Also, the position of these horns differs: often they are located directly on top of the eye socket but with YPM 1831 they originate at the rear edge of the orbit. Likewise, there is a variation in the form of the nose horn. YPM 1831 and to a lesser extent YPM 1830 have a straight upright nasal horn but MOR 981, ANSP 15192 and especially MOR 1122 at most possess a low bump. The frill too differs. ANSP 15192 and YPM 1830 have a shield curving upwards at the rear, but the frill of YPM 1831 is nearly flat, though this could be an artefact of restoration. 

The frill of YPM 1831 is also heart-shaped, with a clear midline notch, whereas the rear edge of the other specimens is straight. The frill proportions are quite variable: with YPM 1831 the length-width ratio is 1.26 but MOR 981 has a shield 2.28 times longer than wide. The number of epiparietals is difficult to assess as most fossils seem to have lost them. MOR 981 and MOR 1122 have ten and twelve epiparietals respectively. YPM 1831 has been restored with a fontanelle in the skull roof, which possibly is authentic. Farke also concluded that the degree of variability did not exceed that shown by related genera.

Farke stressed that, apart from the frill, no systematic differences could be found between Torosaurus and Triceratops. All Torosaurus specimens are similar in that they lack a truly long nasal horn and a horizontal arterial groove at the front base of that horn, but Triceratops fossils with the same combination of traits are not uncommon. 

In 2008, Hunt concluded that T. utahensis, contrary to T. latus but similar to Triceratops, possessed a midline epiparietal.

ECHOES FROM THE EOCENE: A WHALE BETWEEN WORLDS

Chrysocetus foudasil 

The impressive skull you see here belongs to Chrysocetus foudasil a member of the Basilosauridae, an ancient family of fully aquatic early whales known as archaeocetes. Though it still bore vestigial hind limbs, it no longer depended on land—a critical evolutionary step from its semi-aquatic ancestors such as Ambulocetus and Protocetus.

Basilosaurids like Chrysocetus, Dorudon, and Basilosaurus ruled the seas of the late Eocene, occupying ecological roles much like today’s dolphins and orcas. 

Basilosaurus grew into a serpent-like giant over 15 meters long, while Dorudon was smaller, sleeker, and likely faster. Chrysocetus was somewhere in between—mid-sized, streamlined, and adapted for powerful undulating swimming.

These early whales represent a pivotal stage in cetacean evolution. They bridge the gap between the land-dwelling artiodactyl ancestors (even-toed ungulates like deer and hippos) and the fully marine mysticetes (baleen whales) and odontocetes (toothed whales) that would later diversify in the Oligocene.

Looking at their remains, we are seeing a window into our world when whales were still learning to be whales—a fleeting evolutionary moment preserved in Moroccan stone, where golden bones tell the story of an ocean in transition.

A DAY IN THE LIFE OF A HADROSAUR

Glorious Parasaurolophus art work by Daniel Eskridge

Morning mist curls along the banks of a wide, slow river. The air is heavy with the earthy scent of wet ferns and moss, tinged with the sweet tang of distant flowering trees. 

Sunlight filters through the canopy of towering conifers, catching the mist in golden rays that dance across the forest floor. 

In the dappled light, a herd of Edmontosaurus—duck-billed hadrosaurs—trundle slowly along the muddy bank. 

Their broad, flattened snouts graze the lush vegetation as they move, leaves crunching softly underfoot. 

Occasionally, one lifts its head, nostrils flaring as it senses the faint rustle of small mammals or the distant call of a Troodon hunting nearby. The low, resonant calls of the herd echo through the valley—a combination of hums, grunts, and whistling notes, a complex social language that signals alertness or contentment.

Around the herd, the world teems with life. Tiny lizards dart among fallen logs. Feathered dinosaurs like Caudipteryx flit through the branches, their wings rustling against the leaves. In the sky, pterosaurs wheel silently, shadowing the riverbanks, while fish occasionally leap from the water, disturbing the mirrored surface. 

A Tyrannosaurus stalks at a distance, its presence felt more than seen, tension rippling through the herd as they lift their heads in unison, scanning the forest edge. Yet for now, they continue to feed, grazing on conifers, ferns, and flowering plants, their broad dental batteries efficiently shearing tough plant material.

As the sun climbs higher, the herd’s rhythm shifts. Juveniles cluster together near the center of the group, protected by adults forming a loose perimeter. Mothers communicate constantly with low-frequency hums that travel through the ground, letting their young know it is safe to graze. Each hadrosaur maintains a personal space, yet the herd moves as a fluid unit, coordinated by sight, sound, and subtle gestures. 

Occasionally, two adults nuzzle briefly or bump heads—a gentle reinforcement of social bonds within the herd.

By midday, the river becomes a focal point. Watering holes are where wildlife gather. 

Hadrosaurs wade into shallow water, stirring the mud with their broad feet, creating a chorus of splashes and grunts. The water’s surface reflects the glittering canopy above, disturbed only by the occasional leap of fish or the landing of a pterosaur. 

Here, the herd drinks, cools down, and reorients itself to the sun’s angle. Younglings playfully chase each other through the shallows, their calls mingling with the rhythmic lapping of water. Predators lurk nearby, and the herd’s vigilance never wavers—any unusual sound or movement triggers a wave of alert postures, heads lifting in unison, tails flicking nervously.

As afternoon wanes, the herd moves toward forested areas, seeking shade. The scent of resin from conifers mingles with the damp earth, masking the smell of predators. The larger adults lead, while subadults and juveniles follow, practicing the complex patterns of herd movement they will rely on for survival. 

The subtle vibrational signals—footsteps, tail swishes, body shifts—help coordinate the group over distances that the eyes alone cannot manage. Within these social structures, older hadrosaurs seem to guide the young, showing where the most nutritious plants grow and signaling which areas are safe.

By evening, the forest becomes alive with nocturnal creatures. Crickets and insects add a constant hum to the air, while small mammals rustle in the underbrush. The herd settles in a sheltered clearing, forming protective clusters. 

Some adults lower themselves to rest, heads tucked under broad forelimbs, while juveniles huddle close, still vocalizing softly, practicing the calls they will use to communicate when they reach adulthood. 

The sounds of the night—rustling leaves, distant predator calls, and the gentle low-frequency hums of the hadrosaurs—create a layered, symphonic soundscape of life at the end of a Cretaceous day.

The world of hadrosaurs was far from solitary—their forests, riverbanks, and floodplains teemed with life, forming a complex and interconnected ecosystem. While the herd grazed, the air vibrated with the calls of feathered dinosaurs like Microraptor flitting between branches, occasionally diving to snatch insects from the foliage. Small mammals—ancestors of shrews and multituberculates—scuttled across the forest floor, their tiny claws stirring the moss and fallen leaves.

Predators lurked at every edge. Tyrannosaurus and Albertosaurus prowled open plains and forest margins, stalking both hadrosaurs and smaller herbivores. Juvenile hadrosaurs, particularly vulnerable, relied on the protective circle of adults, whose heads, tails, and bodies created a living barrier. Even crocodilians patrolled the rivers, their eyes breaking the water’s surface as they waited for an unwary hadrosaur to drink or bathe.

But the landscape was not only danger and vigilance. Insects buzzed among flowering angiosperms, pollinating as they fed, while dragonfly-like odonates skimmed over ponds and streams. Frogs croaked from the damp undergrowth, adding a pulsing rhythm to the daily soundscape. Trees, ferns, and cycads provided more than food; their dense canopies offered shelter from predators and sun, while fallen logs and leaf litter created microhabitats for countless invertebrates.

Seasonal changes added another layer of complexity. During rainy months, riverbanks became muddy feeding grounds, leaving tracks that we find and study today. 

In drier periods, herds migrated across plains and valleys, guided by the scent of water and fresh vegetation. The interplay of predators, prey, plants, and smaller animals created a dynamic, constantly shifting stage where survival depended on vigilance, cooperation, and adaptability.

Through fossil evidence—trackways, bone beds, and stomach content analysis—we can reconstruct this rich tapestry. Imagining the sensory richness: the smell of resin and damp soil, the low hum of a herd communicating, the distant roar of predators, and the flash of feathered wings overhead, gives life to a world that has been silent for 66 million years. 

In that world, hadrosaurs were central actors in a vibrant, thriving ecosystem. Hadrosaurs were not solitary wanderers but highly social beings, capable of complex communication, coordinated group behavior, and protective care of their young. 

The hadrosaurs you see in this post are Parasaurolophus — one of the last of the duckbills to roam the Earth and their great crests were the original trumpets. We now know that their bizarre head adornments help them produce a low B-Flat or Bb. This is the same B-Flat you hear wind ensembles tune to with the help of their tuba, horn or clarinet players.

I imagine them signaling to the troops with their trumpeting sound carried on the winds similar to the bugle-horn call of an elephant.

Imagining a day in their life—from morning grazing along rivers to evening rest in the forest—reveals the richness of their world, teeming with interactions and sensory experiences that echo across millions of years.

For those that love paleo art, check out the work of Daniel Eskridge (shared with permission here) to see more of his work and purchase some to bring into your world by visiting:https://daniel-eskridge.pixels.com/

FOSSIL HUNTRESS PALEONTOLOGY PODCAST

Step into deep time with The Fossil Huntress Podcast—a journey through the ancient heartbeat of our planet.

Close your eyes and imagine the world as it once was: strange seas teeming with ammonites and trilobites, ichthyosaurs and mosasaurs, fern-filled forests echoing with the footsteps of dinosaurs, and sun-warmed badlands whispering secrets from ages long past.

Together, we’ll explore Earth’s great fossil treasures—places where time slows and stone remembers. From sacred landscapes to world-famous dig sites, each episode unearths the science and stories that connect us to all who have ever lived, swum, or flown across this incredible planet.

This is a podcast about discovery, deep history, and the wonder of life itself. I'll share what you want to bring with you to enjoy your time in the field and adventure stories from my time there. 

From the tiniest single-celled ancestors to the mighty creatures that once ruled the Earth, you’ll hear how fossils tell the tale of change, resilience, and renewal—the discoveries that had me whoop with joy and the crushing defeat of a poorly split piece of shale.

So grab your curiosity, favourite the show, and come fossil-hunting through time with me—one ancient adventure at a time for some family-friendly fun. 

Head on over to the Fossil Huntress Podcast on Spotify, Apple or your favourite streaming service. The latest episode answers the question, "What Killed the Dinosaurs?" Currently streaming in 116 countries. 

SMILODON NORTH OF THE 49TH PARALLEL

This fierce predator with the luxurious coat is Smilodon fatalis — a compact but robust killer that weighed in around 160 to 280 kg and was 1.5 - 2.2 metres long.

Smilodon is a genus of the extinct machairodont subfamily of the felids. It is one of the most famous prehistoric mammals and the best known saber-toothed cat. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats.

Up until a few years ago, all the great fossil specimens of this apex predator were found south of us in the United States. That was until some interesting bones from Medicine Hat, Alberta got a second look.

A few years ago, a fossil specimen caught the eye of researcher Ashley Reynolds as she was rummaging through the collections at the Royal Ontario Museum in Toronto. 

Back in the 1960s,  University of Toronto palaeontologist C.S. Churcher and his team had collected and donated more than 1,200 specimens from their many field seasons scouring the bluffs of the South Saskatchewan River near Medicine Hat, Alberta.

Churcher is a delightful storyteller and a palaeontologist with a keen eye. I had the very great pleasure of listening to many of his talks out at the University of British Columbia and a few Vancouver Paleontological Society meetings in the mid-2000s. 

"Rufus" was a thoroughly charming storyteller and shared many of his adventures from the field. 

He moved out to the West Coast for his retirement, first to Gabriola Island then to Victoria, but his keen love of the science kept him giving talks to enthralled listeners keen to hear about his survey of the Dakhleh Oasis in the Western Desert of Egypt, geomorphology, stratigraphy, recent biology, Pleistocene and Holocene lithic cultures, insights learned from Neolithic Islamic pottery to Roman settlements.

The specimens he had collected had been roughly sorted but never examined in detail. Reynolds, who was researching the growth patterns and life histories of extinct cats saw a familiar-looking bone from an ancient cat's right front paw. That tiny paw bone had reached through time and was positively identified as Canada's first Smilodon.

These Apex Predators used their exceptionally long upper canine teeth to hunt large mammals. 

Isotopes preserved in the bones of S. fatalis in the La Brea Tar Pits in California tell us that they liked to dine on bison (Bison antiquus) and camels (Camelops) along with deer and tapirs. Smilodon is thought to have killed its prey by holding it still with its forelimbs and biting it. And that was quite the bite!

Their razor-sharp incisors were arranged in an arch. Once they bit down, the teeth would hold their prey still and stabilize it while the canine bite was delivered — and what a bite that was. They could open their mouths a full 120 degrees.

Smilodon died out at the same time that most North and South American megafauna disappeared, about 10,000 years ago. Its reliance on large animals has been proposed as the cause of its extinction, along with climate change and competition with other species. 

SAILS OF THE PERMIAN: DIMETRODON

Dimetrodon by Daniel Eskridge

In the steamy forests of the early Permian, some 295 million years ago, a Dimetrodon prowls through a world that feels both alien and oddly familiar. 

The forest hums with insect life, and the air hangs heavy with the scent of wet soil and decaying vegetation. 

Towering above are stands of lycopsids, early relatives of modern clubmosses, their scaly trunks reaching for the pale sun. 

Ferns carpet the forest floor, interwoven with the roots of primitive conifers. Between them flow sluggish streams, their surfaces shimmering with pollen and the movements of darting amphibians.

Through this primeval landscape moves Dimetrodon—muscular, deliberate, and unmistakable. Its back is crowned with a tall, elegant neural sail, formed by elongated vertebral spines connected by stretched skin. As dawn light breaks through the canopy, the sail glows amber and crimson, absorbing warmth to jumpstart its cold-blooded metabolism. 

Dimetrodon by Daniel Eskridge

In a world of fluctuating temperatures, such thermoregulation was a powerful evolutionary advantage. By mid-morning, the great predator is alert, its metabolism primed for the hunt.

A rustle in the underbrush betrays the movement of smaller synapsids—perhaps an Edaphosaurus, a plant-eater with its own sail, though broader and dotted with crossbars. Dimetrodon lowers its head and advances silently, each step careful, practiced. Its jaws, lined with serrated, ziphodont teeth, were perfectly adapted for slicing through flesh. 

Unlike the simple cone-shaped teeth of earlier reptiles, Dimetrodon’s dentition reveals its lineage as a synapsid—a group that would, through deep evolutionary time, give rise to mammals, including us.

Despite its reptilian appearance, Dimetrodon was not a dinosaur. It lived more than 40 million years before the first dinosaurs appeared. Its lineage represents an earlier, distinct branch on the tree of life: the pelycosaurs, the dominant land vertebrates of the Permian. 

These creatures were part of the great synapsid radiation, experimenting with new body plans and ecological roles in a rapidly changing world. Dimetrodon’s sail, once thought to serve purely for display, likely functioned as a thermal regulator, allowing it to warm up quickly in the morning and cool down in the heat of the day. 

Some also propose that the sail could have been a signal structure—flashing color patterns to warn rivals or attract mates among the ferns and cycads.

In the murky shallows nearby, lungfish burrow into the mud, preparing for the dry season. Amphibians the size of crocodiles lounge in the shallows, their nostrils barely above water. 

Dimetrodon may have been primarily a terrestrial hunter, but it was never far from the wetlands where prey was abundant. A sudden splash draws its attention—a large amphibian, perhaps a Diplocaulus, with its strange boomerang-shaped head, breaking the surface. Dimetrodon’s muscles tense; the predator lunges, jaws snapping shut with a crack that echoes through the forest. The water churns, then stills. A moment later, the sail-backed hunter emerges, victorious, dragging its meal to the shore.

The Permian ecosystem was one of transition—between the lush coal swamps of the Carboniferous and the arid supercontinent of Pangaea to come. Forests gave way to open plains and deserts, forcing animals to adapt or perish. Dimetrodon thrived in this environment for millions of years before disappearing in the changing climates of the late Permian, replaced by more advanced therapsids, the true precursors to mammals.

We find the fossils of Dimetrodon across North America, particularly in the Texas Red Beds and parts of Oklahoma, their bones preserved in ancient floodplain sediments. These remains—skulls, vertebrae, and the distinctive spines of its sail—offer us a window into deep time, to an age before dinosaurs, when the world was still finding its balance between reptile and mammal, swamp and desert, day and night.

Beneath the humid canopy of the Permian, Dimetrodon was master of its realm—a creature of sunlight and shadow, its sail gleaming like a living flame against the green gloom of the world’s first great forests.