Saturday, June 21, 2014

Prehistoric Warfare: a new fictional series. Episode 1: Liliensternus vs Teratosaurus

Now for something different. In 2004, Animal Planet showed as new series called Animal Face Off, a series reconstructing conflicts between coexisting animals. While the execution was clumsy and lacking, the concept is strong and I think easily applied to prehistoric fauna.  Ideally, there would be professionals discussing the situations, but unfortunately, you have only me. First I will compare the animals, and then depict their behavior, before concluding with the final battle.  The outcome will be my personal opinion; and there would be many times when the outcome would be decidedly different. This is not a scientific consensus, but one researcher’s opinion.

We all love dinosaur battles. They’re always a high point in a film. It’s childish, but it’s just plain fun. So, I’m hoping to use this opportunity to use this almost-universal appeal to get people thinking and talking about ecology, biomechanics, and behavior. Only one or two of these stories will be based on actual fossils-the rest are likely possibilities that must have happened sometime or another. In real life, animals usually don’t fight on even terms, but it does happen. Sometimes prey turn the tables, sometimes predators quarrel between themselves, but it can happen. I hope you enjoy this. Again, first I will have two scenes, one for each animal showing them in their habitat and showcasing their particular skills, then finally concluding with a battle between the two.


This first duel is between the first big dinosaur predator and a rival first mistaken for that same achievement. The former is Liliensternus, a gracile coelophysid and the latter Teratosaurus, an armored rauisuchid.Teratosaurus was the largest predator of the time and place, with Liliensternus a close second.

The time is 220 million years ago in the age of the late Triassic called the Norian. The place is what is now the Czech Republic in the area once called Bohemia. The world is warm and seasonal, with the rivers separated from the dry inland by lush forest.

Right now, it’s morning. The big dicynodonts are still asleep. The biggest animal here, the dinosaur Plateosaurus, is warm blooded, but most of the herd is snoring. The morning belongs to the small; cynodonts return to their burrows and the paradinosaur Silesaurus have already begun their day. Carnivorous theropod dinosaurs wake with them. The tiny Procompsognathus is no threat to the Silesaurus as they forage for seeds, fruits, buds, lizards and, invertebrates. The giant predator rauisuchians can't outrun them without getting close enough to easily spot. Even the increasingly rare Ornithosuchus isn't nimble enough catch even a large adult Silesaurus. However they're not safe. Procompsognathus has a giant cousin; fast and strong enough to consider the former a mouthful.

This Liliensternus has been eating Silesaurs and smaller dinosaurs like Thecodontosaurus since it reached maturity.  This particular cock, maleness advertised by his bright red crest, has not only inherited thousands of generations of a superb physiological evolution but a combination of inherited and learned hunting behaviors.

Let's see one hunt now. The Liliensternus cock uses the cover of the forest to approach a gaggle of Silesaurus. Their social system is pretty primitive; there's no sentry no alarm. Their defense is speed and it's usually enough. When Liliensternus bursts from his cover, they instinctively run. It's usually enough; but not this time.

 The Silesaurs are used to being able to outpace the short bursts of the rauisuchids, which have increasingly turned to bipedalism in order to catch up.  Lilienstaernus is not only a biped, but one build for speed. The long, slim legs are powered by powerful femoral muscles, and the head and neck are slim and light for rapid movement. The front claws have evolved from weight-bearing like a rauisuchid to long, lithe, and tipped with curved claws for catching prey. The final blow is that despite its size, Liliensternus is light, and the length of its legs allow for strides longer than the body of a Silesaur.

Soon he’s on top of a Silesaur, which tries to outmaneuver him. Quick jumps and turns would stagger a Teratosaurus, but the sturdy, flexible ankles of Liliensternus let him keep up. The head darts forward, the curved teeth slashing at the tail of the Silesaurus. It stumbles, but the second head strike misses the body as it swerves again.  The Silesaurus leaps over a fallen log, and the Liliensternus’ claws lash out. One three-clawed hand slashes into the thigh of the Silesaurus, not a crippling wound but it’s enough.

The strike unbalances it, and the prey flops forwards and onto its side. It’s too late for the Silesaurus to right himself; the Liliensternus is on him. A taloned foot slams down on the fallen archosaur’s hip, pinning it to the ground. Now the swift jaws of Liliensternus, slender but lined with sharp, serrated, and backwards-curved teeth, can finally go into play. The slender jaws aren’t bone-crushing or flesh tearing; the kill comes from slashing strokes to the blood vessels. One carefully aimed bite severs an artery, another rips open the windpipe. The struggling stops with a few involuntary spasms as the small Silesaur brain shuts down completely.

Liliensternus wastes no time getting to feeding. There’s no bone-crushing here; it’s precise flesh ripping like a bird of prey mixed with a monitor lizard. Morsels of meat are ripped off, sliced up by quick snaps of the jaws, and swallowed down the Liliensternus’ long esophagus. Endothermic animals like Liliensternus need a lot of food, and so it won’t be long before he makes another hunt. Sometimes he gets lucky, sometimes fortune turns against him; it’s the way of the predator. He might try his luck against giant dicynodont or armored Stagonolepis, but more likely their juveniles would be more promising. He might hunt an Efrassia or young Plateosaur, or a Metoposaurus that is too close to water. A predator can never afford to be choosy-just as long as he can bring it down, he will try it.

An Efrassia is on the menu, however, for the other predator in the area. By the river, the horsetails grow high and dense. A herd of Plateosaurus browses, using their short but powerful arms and curved claws in conjunction to their long necks to grab stalks and bite off the tender tips and younger stems. It’s tough, gritty foods, but the broad teeth do their job. While dicynodonts deal with tough and difficult food by slicing it to bits with their sharp beaks while silesaurs and aetosaurs prefer more tender shoots and roots, these large dinosaurs have grown larger and larger in order to have long, elaborate digestive systems to process food.  They’re bipedal now, but their even larger Jurassic successors will be forced to be quadrupeds from sheer weight.

Plateosaurus’ size also makes it hard to attack-Liliensternus wouldn’t dare fight a healthy adult and the small juveniles must be picked off carefully from the large herds. However, they are not entirely safe. Hidden in the horsetails, carefully smelling the winds, is the top predator of the land. He’s big; as big as a saltwater crocodile, but an endotherm. His weight and bad ankles prevent him from reaching the speeds of a Liliensternus, but his long hind limbs are powerful enough to propel him on bipedal lunges that can easily outpace even young Plateosaurus.

He smells the herd, but he also smells another, new scent. It’s similar, but not the same. It’s food, like most animal scents for Teratosaurus. Even other Teratosaurus must be confronted. The main reason Teratosaurus retains a mail coat of osteoderms is from these encounters, and this one has the scars to prove a long record of fighting other Teratosaurus.

The scent is from a relative of Plateosaurus, Efraasia. Efraasia is smaller than the Plateosaurus; only slightly longer than Teratosaurus and just as bulky. It’s more basal than Plateosaurus; a gracile animal like its ancestors, with longer, slenderer limbs and a slim body. It’s still a large animal, with large claws capable of killing an attacker with a single blow. However, they live in smaller groups than Plateosaurus, and this one is alone.

The wind is blowing so that she can’t smell the predator. Periodically, she turns her small head on her long neck to scan the horizon, but spends most of her time grazing. Endoterms like Efraasia need to eat a lot in order to maintain their level of activity, a trade off compared to the more sluggish phytosaurs and metoposaurs lining the riverbank. Instead of heating, endotherms spend their time eating, and eating constantly.

This fact is not unclear to the Teratosaurus, who has drawn closer to the scent, creeping in on all fours. His weight is too much for a Liliensternus-style run; he needs to get closer. The wind is with him, and he’s going as fast as possible given his weak front limbs. Soon he’ll be in range.

Efraasia is still eating. She’s an adult, at full size, but she has witnessed earlier attacks and is still cautious. Memories for small-brained animals like her are vague, but the association of certain smells and sights with the emotions of fear are strong. If she smelled Teratosaurus before he gets close, she can run or fight enough to make Teratosaurus change its mind on the calories expended.

A distant splash distracts them. One of the amphibians, Cyclotosaurus has attempted to snatch the small pterosaur Eudimorphidon as it skims for fish. The pterosaur is too fast, and the 2-foot jaws snap on the air trailing its long tail. There is a brief pause. The Eudimorphodon flutters to the safety of a nearby tree, but she’ll be fishing soon again. The Cyclotosaurus submerges to wait for another opportunity. Both Efraasia and Teratosaurus pause.

He’s close; well within range but he’s making sure. Efraasia returns to eating. Soon Teratosaurus is within 30 feet of the target.   Suddenly, everything changes. The wind shifts; Teratosaurus has lost the scent but his eyes are keen enough to see the target this close. However, the wind’s change brings over Teratosaurus’ scene to Efraasia. She doesn’t know where he is exactly, but she knows an nemesis is here and her instincts kick in. 

Everything happens very quickly in an ambush. Efraasia raises herself to full height so that her tail sweeps the detritus on the ground. She stiffens, raising her snout to catch the smell and her arms open wide, preparing her claws for combat. Teratosaurus bursts into action; with a kick he’s off the ground, front limbs drawing up to his chest and neck while his hind limbs push off his massive bulk. He’s sprinting now, outpacing any quadruped in the swamp.

Now he’s on top of her. She turns to confront her attacker but even as she pivots with a strong push of her hind foot, the Teratosaurus collides with Efrassia. 650 lbs of armored predator crash into the slender sauromodomorph, and she crushes yards of horsetails into the mud with her fall. Teratosaurus’ jaws snap instinctively, catching her clawed right paw before they hit the ground. A sharp twist of the rauisuchid’s powerful neck snaps the bone, but Efraasia’s other claw lashes up to slash at the offending head.

Teratosaurus roars in pain-his head is robust and the blow far from lethal, but the 5-inch claws have cut into his face and drawn blood. Involuntarily, he releases his grip, and the struggling Efraasia manages to untangle their legs and push Teratosaurus off.  She tries to right herself, but it’s too late. Teratosaurus’ front legs are oriented to face the ground, making them good for recovering balance or propping up the body until the hind legs lift, while Efraasia has already begun the saurichian process of bipedalism Her clawed paws face inwardly to act as rakes and weapons, useless as props. She’s a better biped than Teratosaurus, but he can recover from falls much easier. 

His tail pushes against the ground then raises to balance his heavy body as his front limbs push off again. He’s got precious seconds left of energy-they’re both endotherms, but large ones, meaning that they must run on adrenal and thermal inertia after a short burst of activity. Their cold-blooded ancestors would have called it a draw and he would have gone hungry. Warm blooded top predators require a lot of food and a lot of energy for that food in an endless cycle still done today from lions chasing gazelles daily in the Serengeti, cats and dogs relentlessly pursuing squirrels, mice, and birds in parks, and humans periodically interrupting their activity for a bagel and coffee.

Teratosaurus’ lunge has to count this time, and he reaches up his powerful head in one last attack. His mouth, like many other predatory archosaurs, is his only offensive weapon, and that means literally putting his head on the line. The jaw opens wide-like all diapsids, his teeth are arranged in identical rows, but every tooth is a medially compressed, recurved, serrated knife. A push of one foot propels him with his mouth open at the weak point of every tetrapod-the throat. Efraasia’s still in shock from the mauling of her arm and her heavy fall, and she’s still trying to find her footing. She can’t react fast enough. One last swing of her left claw scrapes uselessly off the dorsal armor of Teratosaurus, and his jaws close on her neck.

The death is swift and efficient, ending her agony. The sharp teeth cut through the skin to sever the windpipe and arteries, biting even into the spine with the huge maxillary teeth. A twisting shake of his head makes sure the neck is broken and her blood winds up on his mandible and on the pulped mixture of mud and plants rather than into her brain. Her death cry is cut off before it can even begin, a gargled gasp at most.

The “kill” switch in Teratosaurus’ brain switches to “feed” at this point, and he releases Efraasia’s neck as he falls back to all fours. He quickly moves to her thorax and abdomen, ripping it open with another bite and tearing into her nutrient-rich organs. Muscles may be more palatable to the human tongue, but the liver, kidneys, and stomach are packed full of vitamins and other nutrients, and like all predators, he eats those first. He doesn’t make a kill every day, so he must eat efficiently and quickly to beat scavengers.

He may be the apex predator, but he’s not alone. The claw marks on his face and back join many others on his body. He’s been attacked by dinosaur predators, phytosaurs, Ornithosuchus, and especially other rauisuchians. Later predators will evolve display structures on their heads or complex social rituals to diminish injury (indeed, Liliensternus always has), but rauisuchians instead bear the bony mail of their crocodile, aetosaur, and phytosaur kin.

A dinosauroid, Saltopus, suddenly runs over and snatches a strip of meat from the gory wound and runs when Teratosaurus growls at it. This will only be the first. Already pterosaurs are circling and he can hear a Palaeorhinus splashing from deeper waters to scavenge. At any moment, another Teratosaurus could come and claim the kill. Within five minutes, he’s not only finished the organs but torn off thigh and tail flesh. The mauled arm and neck he leaves to the scavengers.

In nature today, predators tend to avoid each other unless there’s enough of a size difference for the larger to view the smaller as prey. Confrontations are common, but injuries are avoided at all costs.  However, there is another exception, and that’s desperation, coming from hunger. And so it is in the dry season of Triassic Germany. During the wet season, the rivers well and the forests thrive along them. However, in the dry season, food is harder to come by-migration and death depopulate areas. This dry season is particularly bad. The Plateosaurs were the first to leave, then the Efraasia and Thecodontosaurs. The old dicynodont is gone, and the silesaurs have dwindled. A few rugged aetosaurs hold out, but the rest have moved on in a massive armored herd. The pterosaurs have moved upstream to follow the insects and fish, as have the amphibians and phytosaurs. A few Metoposaurus remain in stupored hibernation, buried safely underground.  Likewise, their predators have moved on, but this time there’s just enough food to stay, but not enough to avoid a fight.

Liliensternus has found a Metoposaur. This huge flat-head amphibian was once the terror of the waterways for a hundred million years, but phytosaurs provide stiff competition for their fish prey. Now the rivals must either race each other to the remaining fish, or sit and wait for the rains. The rains should have been here by now-the world is brown instead of green, and the mighty river now barely a trickle. The last week a dozen Metoposaurs died together in a pile, providing rich pickings for Liliensternus and Teratosaurus, and they shared their table. This time, it’s only one.

Hidden in the still-moist mud, the Metoposaur is sound asleep. He won’t wake up for more than a few seconds. The moment Liliensternus finds his prey, he attacks. The groggy amphibian is quickly dispatched.  Liliensternus needed this kill; he’s an endotherm like most of the animals here, and his metabolism requires a great deal of meat.  To survive, he must be faster, stronger, and luckier than his competitors.

This time he’s not fast enough to avoid attention. Even if it was just a nymph, Teratosaurus would find it out with a keen sense of smell. This is an adult, 10 feet long and big enough to keep any predator satisfied for days. Liliensternus sees movement out of the corner of his eye, and he turns to confront the intruder.

Roaring is not used during the hunt, usually confined to disputes with sexual rivals. This time, however, the deadly duet is sung over this vital morsel. Liliensternus hisses, shaking his head to flash his bright red crest. Teratosaurus lets out a long bellow, booming across the landscape.  They snap their jaws, adding percussion to the melody, flashing their sharp teeth.  Lilensternus whips his lithe tail, and Teratosaurus responds by swaying his heavier tail.   As their close, they rear up.

This usually works. Neither animal is intelligent, but they know enough to back down to superior size. Teratosaurus weighs 600 lbs to the Liliensternus’ 450, both healthy adults, but Liliensternus is not going to let his prey go. He’s hungry, and he won’t be chased off of a kill this important. He puts a tridactyl foot on the Metoposaur and leans forward with a deep hiss.  Teratosaurus rears up again with a bellow, coming down with an impact that creates a small cloud of dust.

Fights are gambles by their nature-the risk is crippling injuries and death, but the rewards are survival to see the next season to reproduce. Liliensternus has fended off phytosaurs from his kills, while Teratosaurus has chased off dozens of dinosaur rivals in his time. This should be working for either, but they’ve canceled each other out.

Teratosaurus makes the first blow-he bounds forward on all four legs with his mouth open. It’s the usual strategy for rivals-they would collide, shove each other with their front feet and wrestle with their jaws, and the other would give way. Liliensternus, however, doesn’t charge-with a nimble step of his long legs, he jumps off the carcass to flank Teratosaurus.

Teratosaurus assumes a quick victory, moving to grasp the metoposaur with his mouth, but a stinging pain behind his shoulder interrupts him. He turns, releasing his grip to snap at the attacker. Again, the Lilensternus avoids the attack, leaping backwards and attempting another flank attack.

He’s done this before; circling around aetosaurs and phytosaurs, avoiding their weapons while delivering nip after nip. His inner ear is excellent, giving him balance to dodge in and out, aiming at the underbelly and flanks of prey. This first strike only hit armor-the keratin-covered bony mail can blunt even his serrated teeth. This time, he aims for the side, below the armor. He hits, drawing blood. Again the Teratosaurus counterattacks, but is too slow.

Another bite lands on a front limb. It’s dangerously close to his throat. Rauisuchids are well-armored, but their throats are bare. Another bite attacks his hip, but the armor holds true and the teeth just glance off the scales.  Teratosaurus swipes his tail, landing a hit on the dinosaur. Liliensternus stumbles back, with large welts now glowing on his brown skin.  Imitating the attack, Lilensternus pivots himself and slashes at Teratosaurus with his tail. The impact is lighting fast, but again the armor holds true and only makes the other predator blink and cough.

Lilensternus’ speed is his main weapon, and it’s a deadly one. Teratosaurus charges again, but bites only dust kicked up by the swift dinosaur. The black and grey rauisuchid is turning brown from dust, with bright red spots indicating the bloody wounds. Liliensternus has another major weapon-stamina. He’s lighter than Teratosaurus, and his hollow bones and unarmored body require less effort to move around. He’s not tired yet; he defeated the phytosaurs by exhausting them.

Teratosaurus isn’t finished yet, however; he’s an endotherm himself, and surprisingly nimble. As Liliensternus tries to rip open his thigh, the raiusuchid’s powerful tail slams into him again. Quadrupedal movement may be slower for Teratosaurus, but it gives him great turning ability. As the tail strikes the Liliensternus’ neck, dazing him with whiplash, Teratosaurus uses that same movement to turn around, push off with his hind legs, and surge at his enemy.

This time, Liliensternus is too close and too stunned to dodge. The front feet, tiny but backed by hundreds of pounds of weight, of Teratosaurus slam into his side, and the sheer momentum of the charge shoves the already-disoriented dinosaur to the ground. The first bite breaks Liliensternus’ left shoulder. In defiance, he twists his neck to bite. His teeth tear into Teratosaurus’ face, but the slender theropod jaws are not bone-breakers and Teratosaurus’ skull is far too sturdy.

Whipping his own head, Teratosaurus throws off Liliensternus’ bite. For a second they’re eye to eye. Their heads are parallel, yellow eyes glaring at each other. Then Teratosaurus shifts his weight to go into the kill. Lilensternus tries strike again, but the giant jaws close down on the back of his skull, just between the end of the crest and his long neck.  One broad tooth breaks off as it pierces the bone of Liliensternus’ skull. The other teeth shred the jugular artery, the windpipe and even sever the spinal chord as Teratosaurus sinks in his bite and twists his head. Phytosaurs, like crocodiles, must twist their bodies to tear off flesh, but Rauisuchids, like their dinosaur rivals, have powerful necks used to tear prey limb from limb with powerful twists. And with this twist, he kills Liliensternus. Another twist rips off his head entirely.

Teratosaurus usually is harassed by other predators and scavengers, but they are rare and scattered here and now. Nevertheless, he tears into the Metoposaurus with relish, wolfing down the slightly slimy flesh. A human would think of the meat as a beef to frog’s chicken, but Teratosaurus cares nothing about the taste, only that it’s there. He stays by the carcasses for the next few days. As soon as the last of the Metoposaurus is gone, he begins on Liliensternus. Carcasses are all alike-there is no honor code between predators. Teratosaurus eats eggs, young, and caracasses alike of any animals he can’t bring down himself. The spine and limbs are still untouched when the rains finally return.

Teratosaurus’ win was from a number of physiological advantages. First, armor protected him from the strategy of attrition, forcing Liliensternus to take fewer, more careful attacks. Secondly, his weapons were superior. His feet are small and blunt, but his jaws are large and strong, with powerful teeth more akin to Liliensternus’ Jurassic and Cretaceous descendants than the current dinosaur arsenal, and his tail is long, strong, and armored to be used as a powerful flail. Finally, there’s sheer weight. It makes him slower, but when he makes contact, it’s unstoppable.

Liliensternus, however, will win the evolutionary contest. Teratosaurus may have succeeded Polonosuchus, Ticinosuchus, and Batrachtomus as apex predator, and will have the mighty Smok as his descendant and successor, but the rauisuchid dynasty will end with Smok. The Triassic extinction will sweep the slate. Dicynodonts and silesaurus will perish, with the kin of Plateosaurus and Efrassia replacing them. Aetosaurs will be succeeded by Scelidosaurus, mother to Stegosaurus and Ankylosaurus.  It will be the descendants of Liliensternus that will rule the earth, diversifying, growing in numbers and size and deadliest, reaching the dimensions of Tyrannosaurus, and ruling the skies of the Cenozoic.  But for now, in the late Triassic, they are in the shadow of the ruling dynasty of Teratosaurus and his kin.

1 comment:

  1. This comment has been removed by a blog administrator.