Tyrant Tantrums Part III: A Tyrannical Success

Lets take a look at modern day animals. Specifically, the old world vulture. These living dinosaurs travel the skies in search of the ill, the weak, and the deceased. These animals survive on food that other carnivores would find quite hard to stomach, and get the decaying buffet all to themselves. Their beaks can easily rip into the skin of a typical herbivore, letting them get to the juicy innards of the dead prey animal. When vultures are around, nothing dead is safe from their vicious beaks and tenacious attitude.

Well, almost nothing.



Because no matter how tough the beak of a vulture is, it is almost no match for the thick skin of a mega-mammal.

Vultures aren't the only scavengers around that have a tough time getting through mega-mammal hide. Other carnivores seeking for a jackpot at the death of a giant synapsid have trouble getting through the tough hide. Jackals and marabou storks wait near the carcass, hoping to get some meat while their at it. While a normally thin-skinned wildebeest carcass could be dispatched with relative ease, a thick-skinned elephant or buffalo is more of a challenge. These scavengers and opportunists can only feast on the relatively soft parts of the carcass, like the eyes, nose, and anus. These parts the scavengers can consume, but they won't be able to get the meaty glory just beneath that thick skin. What they need is an animal that will be attracted to the carcass, can efficiently open it up, but will leave enough food behind for the scavengers after its done eating.

Enter the one of the savannah's fiercest predators: The spotted hyena.



This is the bone-crushing master of the land. One bite from this giant member of the feliforme family can crack the leg bones of an elephant, and sliding carnassial teeth mean that thick skin and meat is sliced up and swallowed. An acidic stomach means it too can handle disease-ridden carcasses infested with anthrax and botulism. To all, the spotted hyena is a deadly predator capable of ripping apart anything in its jaws, but to scavengers, this hunter is just a walking can-opener.

Although spotted hyenas are mainly hunters, they will scavenge on the dead or dying. When they find a carcass of an animal as big as a buffalo or a hippo, they will tear into its body cavity with relative ease. When the hyena enters the creature, it starts gorging on the meat, bone, and organs, making most of the opportunity at hand. This is what the scavengers have been waiting for. The hyena has now opened up the body cavity that the vultures and jackals desperately wanted to access. Once the hyena is done eating, the scavengers move in and feast on the leftovers. While hyenas can eat a vast amount of meat and bone in one sitting, there is still plenty left for the vultures, storks, jackals, and other scavengers to gorge themselves on. Unwittingly, the hyena has helped the vultures and other scavengers in getting a mountain of meat.

This behavior of large predators opening carcasses and unwittingly helping smaller carnivores access this normally hard food source is not just seen in hyenas. Bears and wolves also rip open carcasses of thick skinned prey like bison and let smaller carnivores or omnivores get some grub, such as ravens and coyotes. The sea also shows no shortage of this behavior, as great whites and tiger sharks open up whale carcasses and small fish dart in to pick up the scraps of their labor. Scavengers or small predators seem to benefit from a larger predator's "can-opening" behavior, so if modern animals have been documented in doing such behavior, what about ones that no longer walk this planet.

Take for example, Hell Creek (I bet you know what I'm getting at here). At the end of the age of dinosaurs, Hell Creek was home to a numerous amount of predatory reptiles, many of which were a lot beastlier than any modern predator you would find roaming the modern day plains of America and Africa. There was giant lizards related to modern gila monsters, azdarchids, troodontids, the giant caenagthid Anzu, and the giant dromaeosaur Dakotaraptor, whose sickle-like second toe claw is the largest known of any dromaeosaur known, even larger than that of Utahraptor.


(Dakotaraptor killing claw (right) compared to that of Utharaptor's (left). The red circle indicates the larger muscle attachment on the claw of Dakotaraptor)

But despite the massive claws and sharp teeth, Dakotaraptor probably couldn't get into the thick hide of the giant hadrosaurs, ankylosaurs, and ceratopsians at the time. From known skin impressions, we know that the hadrosaurs had potentially extra sturdy skin, that the ankylosaurs had thick armor plating, and that Triceratops has giant scales covering its hide that would have been extremely tough to get through.


(Trike Skin Impressions)

Even the most powerful Dakotaraptor jaws couldn't penetrate through the skin and into the body cavity of such well armored herbivores. Scavenging from the dead of the adults would be extremely hard, as the only parts that would be easy to access would be near the face and feet. A scene with hoards of raptors, azdarchids, troodontids, caenagnathids, and varanids clustered around a recently dead Edmontosaurus, Triceratops, or ankylosaur, unable to get into the body cavity may have been what the situation would have looked like. That is when help arrives. A carcass of any large animal will attract every carnivore for kilometers, but only one can successfully break through the defenses of the regions native mega-herbivores: T. rex.

The massive and pulverizing bite of a fully grown T. rex could smash through the defenses of any herbivore it lived with, even the armor plating of an Ankylosaurus. The enormous pressure of the bite from this apex predator would be enough to get into the body cavity of a thick skinned herbivore and let the little carnivores get their own share of the meal. While they would have to wait in line, there would be enough food by the end of the rex's meal that they could all feast on the spoils, including the otherwise inaccessible bone marrow that would have been easily crunched apart by the rex's repeated and eerily strange mammalian biting style (and such force would put stress on the skull of the animal, which may explain the odd indentations on the maxilla. Sorry to say, but they may have been closer to mechanical stress on the skull than integument indicators, though the rough texture on the rest of the skull suggest a thick covering of some hard substance, like cracked skin similar to wood storks or crocodilians, but with lips).


(Pelvis of a Triceratops, showing signs of repeated biting by a T. rex)

Perhaps, the tyrant king was more than a vicious hunter who everyone fears. Perhaps on some occasions, it unwittingly becomes a helpful scavenger, giving smaller carnivores a chance to get their share of the bargain.

Bone Sawing Theropods: Any Truth to the Hypothesis?

This part of the post is somewhat straying away from T. rex itself and instead focusing on some other theropods. It is quite clear that tyrannosaurids were breaking through and cracking bone, but there seems to have claims of other theropods participating in such behavior of durophagy (Eating of bones, though as far as we know, the only animal that actually makes bone a major part of its diet is the lammergeier or bearded vulture). There are many examples of this. One includes a bone riddled coprolite of an Allosaurus (Identified as such as an Allosaurus tooth was found in the coprolite), roughly around 1.5 meters in length. That makes it the largest theropod coprolite known, larger than even the largest known coprolite of T. rex. It was also riddled with more bone in it, roughly around 50% was made up of bone fragments. Other examples include the plates of stegosaurs having a bite taken out of them along with other theropods having a piece of pelvic bone missing thanks to another theropod scavenging the corpse.

arca.museus.ul.pt/ArcaSite/obj…

Such behavior is fascinating, especially when a tyrannosaurid is not behind the cause. All the specimens are found in rock layers before tyrannosauroids even got substantially large. Obviously, this means that a lot more extinct theropods were eating bone than just the tyrannosaurs, which is quite exciting. How they processed such bone is a bit harder to solve. I mentioned  several times before and his ideas on prehistoric life. One hypothesis that he suggested was that blade toothed theropods processed bone by using a method known as "bone sawing". The theropod in question would grab onto a bone with its mouth, and then shake its neck in a repeated fashion. The rapid movement would allow the sharp teeth to cut through the bone until it was small enough to swallow whole. You can read his posts about it here.

antediluviansalad.blogspot.com…

This method of taking apart bone by slicing it up into manageable pieces to swallow whole seems interesting, but there are a few problems with it. One I want to address is how often it is seen in theopods. As far as I know, it would seem only a certain theropod of the Morrison Formation is the one eating bones in large quantities. Of the giant theropods present, the most likely culprit is probably Allosaurus, as it is the most numerous as well as other reasons elaborated later. When we look at the coprolites, we see that they were jagged shards of bone. Nash suggests this is an action of a "bone saw shimmy", but it could have been just as likely, if perhaps more likely, that the carnivore actually bit and gradually sliced off small sections of bone by tilting its head perpendicular to the bone, and start "gnawing". This is actually seen in some fossils where a sauropod and ornthiscian sacrums look like they have been "gnawed" on by a carnivorous theropod (gnawed in this sense is that the bone was sliced off in tiny sections as the theropod bit into the bone) Now, I know what you are thinking...

"Allosaurus had a weak bite bro. Its said to be weaker than the bite of a lion, so how is it supposed to bite into the bone and mash it apart. HMMMMMMMMMMMMMMMM."

Well, Allosaurus' bite was thought for some time to be quite weak, but it seems that's not the case.


(Bite force reading of mutliple predators, borrowed from this paper: rsbl.royalsocietypublishing.or… )

This is from the 2013 study talking about the bite force of T. rex. While the tyrant king got all the spot light, Allosaurus got in as well. The yellow line is that of Allosaurus. The force exerted is roughly around 8.5 kN, enough force to leave a good mark on bone. The force was also without neck muscles, which means the allosaur could have bitten with even harder force, and the specimen was apparently not fully grown at the time of death (that may be a bit confusing, since nearly all Allosaurus specimens aren't skeletally mature. In this case, its not a baby, but its smaller than the usual Allosaurus specimen). An adult would have bitten harder.

Now, you are probably also stating this...

"Okay, it has a powerful bite, but its got blade like teeth, so how is it gonna bite into bone an actually crunch it?"

Well, I have something for you. Allosaurus teeth aren't blade like in nature as most of you think. Quite the contrary, they were quite beefy.


(Allosaurus tooth, borrowed from the Leigh Valley Museum of Natural History website)

Now couple this with the fact that the skull of Allosaurus is built to withstand a lot of force, which was originally used to support the hatchet hunting style, which I do not agree with strongly. The powerful skull, bite, and teeth all seem to suggest that Allosaurus was probably capable of actually slicing into bone and eating it similarly like tyrannosaurids, albeit not as efficiently. We see this in the fossils of plant eating dinosaurs with parts of their sacrums bitten off. I find it quite intriguing that in most cases, the allosaurs were aiming for the pelvic region when eating bone, which makes sense, seeing as how the pelvic region in quite meaty in sauropods, so they probably aimed for that area first. Heck, this is seen in tyrannosaurids too, as in the previous image where a trike pelvis has been chewed on and raked by a tyrannosaur's teeth (though they first started with the head).

Now we move on to the REAL blade toothed theropods. Could they bone saw or even get into the bone itself? Well, probably not. We only have evidence of non-tyrannosauroids processing bone from the Morrison and Early Cretaceous Japan, which was home to tyrannosauroids (depending on what you think megaraptorans were), which had teeth similar to those Allosaurus. These predators show that non-tyrannosaurid theropods can eat large amounts of bone, but that doesn't mean every single one eats large amounts of bone. Modern carnivorous show this. Many birds of prey and some felids aren't usually eat very little to no bone, while some, like certain vultures, canids, and hyenas constitute much of their meat diet with bone. Extinct theropods have only ever been documented eating large amounts of bone twice, in tyrannosauroids (again, depends on whether a megaraptoran left those score marks in the Japanese sauropod vertebra) and allosaurids (dromaeosaurs have also been shown eating bone, but not in the amounts seen in the other two groups). We also need to take a look at the skull biology. The skulls of derived carcharodontosaurs are very weak, meaning they can't handle stress very effectively. I doubt that bone sawing would remove this problem, as there seems to be plenty of stress of dragging your teeth against bone and shaking your neck in a repeated pattern. These giant hunters were probably avoiding the larger bones (legs, hips, large neck bones) of their prey, feasting on the thick skin, meat, and the more manageable pieces of bone, like the ribs, skull, and the small tail bones. It is interesting to bring up that the "carnosaurs" started out as quite competent eaters of bone, but over time, their skulls became less suited for the business, and shifted towards a pickier diet. In fact, the more basal allosauroids were built closer in design to the tyrannosaurids than their later cousins, with skulls that are built to handle a lot of stress, thick teeth, and a more powerful bite. In fact, their body was closer to that of the tyrant lizards. They were quite barrel-chested and stocky-legged, and even had large caudofemoralis muscles in their tail. The only significantly different things between them are the arms, body size, and tooth differentiation. One should wonder as to why the carnosaurs evolved to render bone less and less efficiently as they continued their reign as top predators, and when they went extinct, their place was taken by the tyrannosauroids. Ironically, the tyrannosauroids started out as flesh renderers and evolved to process and eat through tough meat and bones.

The Success of the Tyrant Lizards

During the end of Cretaceous, the tyrant kings were at their peak performance. They were the largest predators in their environment and were a threat to almost anything they decided to set their keen eyes upon for breakfast, lunch, or dinner (or any non-official time of when they want to eat). They were so successful that they spread to nearly every corner of Laramidia and Asia. Originally, it was thought that the tyrannosaurines were limited to Mid Laramidia and Eastern Asia, but later discoveries would soon change this. In 2013, the discovery of jaw elements from Alaska showed evidence of a tyrannosaurine ruling its lands, 69 million years ago. Named Nanuqsaurus (Meaning "Polar Bear Lizard"), this tyrannosaurine was found living at the top of the world, and because of the harsh climate up in the North Pole, it had to shrink in size to a poultry 5.5 meters, though still a formidable creature for any of its prey items. In 2014, 6 teeth from a tyrannosaurine were found in Mexico, further south than we once realized. The teeth matched T. rex almost perfectly, so they likely belonged to T. rex or a close cousin.

www.researchgate.net/publicati…

But one discovery was quite shocking despite how little attention it got. In 2012, paleontologists published a long dormant specimen of a tyrannosaurine dentary recovered from the fossil beds of Kazakhstan, the last place you would expect a tyrannosaurine.

www.researchgate.net/publicati…


(Kazakhstan tyrannosaurine dentary, borrowed from the paper above)

Another specimen, known from a maxilla, is not published and may be in private hands, but we know of at least one specimen of a tyrannosaurine from this region. We even have found evidence of tyrannosaurines from Russia, from the Kundur region. The specimens are known from phalanges, teeth, claws, and some vertebrae. Such a range is quite impressive for a large predator, and is to be expected. After all, carcharodontosaurines crosses two continents as well, and the megalosaurs managed to invade three 


(by )

Their reign as apex predators also didn't span the last 7 million years of the Cretaceous. In the same year as Nanuqsaurus, another tyrannosaurine was unearthed, this time from the Grand Staircase-Escalante Monument in Utah. It was dubbed Lythronax argestes, or "The Gore King of the Southwest". Measuring just over 7 meters, it wasn't as large as T. rex or Tarbosaurus, but it was a dangerous predator nonetheless. The surprise came when the rock surrounding the fossils were dated. They were around 80 million years old, meaning that this tyrannosaurine precedes all known tyrannosaurines to date by around 4-5 million years. That's not the only thing that was surprising. Lythronax may be one of the most basal tyrannosaurine known, but it had many derived features, including bone-smashing teeth, widening of the back of the skull to increase bite power, forward facing eyes, and a pinched third metatarsal.

journals.plos.org/plosone/arti…


(Skull of Lythronax borrowed from the paper)

Derived traits such as these suggest that Lythronax was not the ancestor of tyrannosaurinae, but in fact a quite late member of the group. The study describing Lythronax suggests that tyrannosaurinae may have originated much earlier, with the authors suggesting that they split off anywhere between the earliest Campanian to before the Late Turonian, but they suggest that the split and radiation took place during the Late Turonian, since a major sea regression period around 91 to 90 million years ago would have allowed the tyrannosaurids to radiate further out and enter new continents, which is what we see in the fossil record. If this is true, than it means tyrannosaurines were on the scene for over 25 million years, which is quite impressive really. Compare that to other large-bodied carnivores: Carcharodontosaurines were around for over 17-20 million years (depending on when Carcharodontosaurus lived), megalosaurines for about 16-17 million years, and allosaurines for just about 8 million years. They also exceed some modern and extinct mammalian predator groups, exceeding the amphicyonines (17.5 million years), felines (so far 9 million years. Now, I'm not saying tyrannosaurines were "better" than the other theropod dinosaurs. There are things that they couldn't do as well as the other theropod groups, such as running fast, agility, processing meat (though I don't think they would have a hard time with ripping into meat), and other things as well, but I would like to note that they do have many traits that most large-bodied theropods didn't have, and those traits that made them almost unique in the dinosaur kingdom may have contributed to their massive success as a group.

Teeth of a Different Kind

When it comes to feeding, the tyrannosaurines were no slouches. As noted before, they are very good at ripping apart and mashing through bone, but they were also good at snipping off flesh. Tyrannosaurids as a whole had dentition unlike any other theropod known. Most theropods had teeth that were more or less in the same shape along the jaw and only differed in size, meaning a dentition more or less designed to rip through flesh and muscle, but isn't very good at processing tougher material, like big bones on a regular basis.


(Borrowed from )

Tyrannosaurines teeth on the other hand differed not only in size, but in shape as well. They had three different sets of teeth, the first set, on the front of the top row, are short and serrated. They are used to scrap off small scraps of flesh, as well as the keratin coating on the frills of Triceratops, as noted in a paper talking about the eating habits of rex (If you are wondering which one, its the one that shows evidence of T. rex ripping the heads off trikes: www.nature.com/news/how-to-eat… ). The second set of teeth are the teeth that do the real damage to prey, ripping off chunks of flesh and bone. They were also the ones that would have dealt the killing blow to their prey, kinda like the canines of modern carnivorans or the teeth seen in crocodilians that are used to grab onto prey. The third set of teeth are the "crunchers", the ones that mash and smash up bone and meat, processing it into tiny bits and pieces for the tyrannosaur to eat whole.


(The scraping teeth of rex compared to stabbing tooth. From Wikipedia)

These different kinds of teeth allowed the tyrannosaurines to access maximum nutritional value from their prey, enabling them to extract the mineral salts and marrow in the bones of their prey. They devour most, if not all of the carcass they are presented with. While the largest tyrannosaurine had the biggest bites, some tyrannosaurines took their crunching power to another level.


(Teratophoneus lower jaw from Carr et. al.)

Teratophoneus is probably the most extreme example of the tyrannosaurine's powerful jaws. Despite being quite small, around 6 meters for the largest known specimen, the jaws were incredibly short and thick with massive teeth. The largest specimen, a large sub-adult (and the specimen pictured above), had incredibly large and stout teeth, perhaps even more stout that the jaws of the largest tyrannosaurs. Being a sub-adult, the skull would have been even more heavily built in the adult. With such deep set jaws, Teratophoneus may have been the tyrannosaurine with the least fussy diet, probably eating anything it wants, perhaps even eating the whole skulls of its prey, something that even the biggest tyrannosaurines have been observed doing.

A Chase for the Long Haul

Among Theropoda, the tyrannosaurines were among the most suited to running. Their legs and feet were built in a way that made them faster than most theropods of similar size. However, despite having more speed related adaptions, the biggest of tyrannosaurines may not have ran any faster than the largest carcharodontosaurs. In an SVP study, mathematical models showed that tyrannosaurines were not much faster than the other giant theropods despite their speed enhanced adaptions, and they most certainly weren't very agile, as another SVP abstract put this in perspective (If you want a look, the abstract can be seen here: antediluviansalad.blogspot.com…). While the giant tyrants may not have been the most agile of hunters, they don't need to be fast to catch their prey. In the same SVP meeting, other studies have shown that while the tyrant kings weren't quite fast or agile, they was a great long distance runners. The third metatarsal was pinched toward the middle, and virtually disappears from sight as it gets closer to the top. The metatarsals are also fuzed together, meaning that there is less jiggling between the bones with each step, which saves energy. More energy is also gained back when the animal lifts its leg up to take the next step, which means the animal wastes less feul on its run. This kind of condition, known as the arctometatarsalian condition, is seen in at least 3 other families: Troodontids, Ornithomimosaurs, and some Oviraptorosaurs. This condition is thought to represent long distance running adaptations, and with the powerful muscles attached to pelvic region and with a femur and tibia ratio eerily similar to that of canids and hyenas (in which they are both the femur and shin bones are pretty much the same length), both long distance runners and hunters, it would seem that the tyrannosaurines were probably taking down prey using a strategy similar to wolves and hyenas, where they chase their prey into exhaustion. However, this seems a bit odd for a over 6 tonne carnivore that can just run up to its prey and take it down quite quickly. Perhaps instead of using it as a hunting method, tyrannosaurines followed their prey wherever they went. We know that the favorite prey of the tyrannosaurs are hadrosaurs and ceratopsians, and both are herd animals, traveling long distances to find food. Perhaps T. rex and its kind never really had a permanent territory. Perhaps they lived a nomadic lifestyle, and followed the herds of ornithiscians that grazed on the plants in the area. They may have followed the herds wherever they went, feasting on the sustainable food source whenever they wanted, and while other items in the area would have been preyed upon, a herd of hadrosaurs or ceratopsians would be the best food source, and with the ability to travel long distances, they can keep up with the herd at all times, and herds of such size may bring tyrants together, so they may not have been total loners (though, they still weren't pack hunters). We even find tyrannosaur skeletons sometimes in close proximity to their prey, such as three Daspletosaurus horneri of various growth stages buried alongside five hadrosaurs. Perhaps the tyrannosaurs were following the herd of hadrosaurs and some stragglers were killed by accompanying tyrants, but the three specimens were probably killed in a feeding frenzy with other tyrants, only to be buried along with their prey, and the bone-bed was found in the Two Medicine Formation, the same place where Maiasaura come in huge herds to lay their eggs. All that food in one spot opens up an even bigger buffet to the tyrannosaurs, so perhaps they not only gorged themselves on the herbivores, but also laid their eggs at the same time as the herds of prey, meaning that their brood's hatching would coincide with the hatching of their prey, which gives them a huge advantage in reaching adult size. There is another trick: Unlike the baby hadrosaurs which were incapable of standing up for a while after they hatch, the baby tyrannosaurs could probably walk fine the day they come out of the egg. This means that the rexlings can go wherever their parents could go, meaning that they can keep up with them as they follow the herds of ceratopsians and hadrosaurs, and because the young hadrosaurs are basically defenseless packets of meat during their first year, and there are multitudes of them (around 30 to 40 in each nest!), that makes them perfect targets for the adults to bring back to their kids, as well as their parents. No wonder nearly 90% of Maisaura don't make it past their first birthday. 


(Figure from Woodward et. al. (2016))

Perhaps the tyrants following their prey wherever it went may explain their sudden invasion. Because hadrosaurs and ceratopsians are migratory animals, they may have made their way across the land bridge that connected North America and Asia at some point. The predators followed their prey, until they found themselves in foreign territory. Gradually this continued, until the tyrannosaurines managed to conquer nearly all the Northern Hemisphere, from Mexico to Kazakhstan. In truth, it was probably their prey that made them conquer the lands of the North.

Taking Over Everything

Another reason as to why the tyrannosaurines were so successful was perhaps their growth. Most large theropods have some differences between their ages, such as leg length. Tyrannosaurines however took this to the next level.


(Jane by )

Tyrannosaurines were incredibly varied in their ontogeny. If you didn't know anything about ontogeny, and you saw a teenage T. rex and an adult T. rex side by side, you would think they were different species, and behaviorally, they would act like different species, but they were in fact the same animal. Such niche partioning between growth stages is seen throughout theropoda, especially the case of Limusaurus (young had a set of large teeth and were omnivores, while adults were beaked and herbivores), but the tyrannosaurines weren't just reducing tooth count, they were changing their entire physiology. Newly hatched tyrannosaurines had large heads with big eyes, excellent for nocturnal hunting, and were extremely long-legged. Juveniles were longer snouted, while teenagers had shorter and smaller skulls, but proportionally thicker and longer legs. The subadults had fewer teeth, but more a stocky build and deeper jaws, but could still run quite fast. Finally, the adults were very robust and built for cracking through the defenses of their tough prey.

The amount of variation between the growth stages lets tyrannosaurines exploit all possible niches. With all the slots filled in, they can have access to an abundant variety of food items as they grow, and as one profession subsides, another takes its place. In fact, exploiting all these niches may have been the reason as to why the tyrannosaurines attained such huge sizes. With more food available through each stage, the body can turn all this food into energy and growth, and turn a 2 year old, 9 kilogram hatchling into a 28 year old, 9 tonne old adult. Taking all the niches also means more food for yourself and no competition. When you see tyrannosaurs dominating an environment, the only substantially large carnivorous theropods you see around are the dromaeosaurs, since they hunt in a different way then the young rexes (Ambushing rather than Pursuit Hunting). With no competition, the young tyrannosaurines can gorge themselves on prey whenever they want, and with the demand for food being very high, they need all the energy they can find to fuel that runner's physique.


(Tarbosaurus bataar juvenile borrowed from here: sci-hub.bz/10.1080/02724634.20…)

(Daspletosaurus horneri juvenile borrowed from Wikipedia)

And think about it, if young tyrannosaurs were eating different kinds of prey at different stages, they can avoid competition with their parents. That means that they aren't a nuisance to their parents for very long, perhaps meaning that they could probably stay together for some time.......that is, until the juveniles start getting too big.

Final Thoughts

The tyrannosaurines were a successful lineage of predators that have been featured multiple times during popular culture. The image of these beasts have been deeply engrained in the media as a creature ambushing large dinosaurs as the norm, when really these tyrants of the dinosaur world were more varied in their diets. They lived in places where water and land meet, and where predators can break the boundaries just to get one step ahead of their prey. They would have eaten the prey living in the water as well as on land, and even perhaps use their own environment to get ahead of their land based food items. We often thought that they were mostly scaly or mostly feathered, when really they were probably more varied in their integumentary choices than we think. The dynamic properties of terrestrial dinosaur skin means that populations can vary in integument among the same species, with more northern groups being more densely feathered than southern populations, and that feathers, skin, and scales can all coexist on the same integument zone, as seen in many extinct and living dinosaurs. The face of the tyrant kings were probably the stuff of nightmares. Instead of a smooth face, they would have possessed thick, "scaly" facial coverings, thickened patches of naked skin on the neck, and bulging protuberances on the sides of their skulls perhaps not dissimilar to some modern wild pigs. The giants were also a much needed commodity for smaller carnivores when presented with a large carcass, opening up the deceased bodies that were too tough for the small to get into. The can-opening behavior seen in tyrannosaurs is in part to their giant jaws, capable of ripping into and gaining as much nutritional value from the animal they killed or scavenged as they can. They were nomads, following the great herds wherever they went, picking off the weak, the ill, and the young, and making most of the great breeding events that their host herds hold every year. These mighty carnivores exploit every niche throughout their ontogeny, making most of their environment, so that they can pass their genes on to the next generation, and this exploitation has allowed them to cross continents, from the subtropics to the Arctic, from North America to Asia, and taking control of every niche they can fit into. Their evolutionary tricks have allowed them to survive for over 25 million years, longer than most subfamilies of large-bodied terrestrial predators, and to spawn the largest of all land predators. They were the most efficient, the most amazing, and the most awe-inspiring predators of their time. Deadly hunters versed in the art of killing and scavenging, able to exploit any opportunity that nature could throw at them, whether it be a new prey to hunt or new land to conquer. If it not for the giant asteroid that slammed Earth 66 million years ago, they may have been still ruling the planet for quite some more time.

Like any predator that has been engrained into our psyche, they were awesome, bro.

To end this, here is a tyrannosaur from , with some of my hypotheses incorporated into it.


For detail, click the "shadeless" setting.

Thanks for Reading!