Huincul Formation, Argentina, 94 Million Years Ago

The light of dawn colors the sky on the horizon with a mix of orange and purple. The land that will one day be Patagonia lies blanketed in a shadow below the sunrise. As the light shines brighter over the hills, the shadow fades revealing a dry, arid landscape. The ground is mainly beige from the sand with small parts of grey from many rocks and pebbles. Scattered throughout are dry shrubs stained in brown and tall araucaria trees with dark green pines. There is also a narrow, shallow river, one that turns the dirt in it and along its edges into soft brown mud.

Despite how empty much of this land seems, it is home to giants. 30 of them stand beside the river stream gulping its muddy water in large chunks. More of them stand by the trees, using their mouths to bite down on and strip the pines off their branches. The ground shakes and quakes even with the smallest of their steps. Like those of an ostrich but much deeper, their booms vibrate for miles around them along with echoing groans and deep grumbling bellows. They are Argentinosaurus, a massive species of sauropod that reaches over 110 feet from head to tail and weighs up to 100 tons. With only the modern-day blue whale outsizing them, they are among the largest animals to ever live. Their skin is primarily a series of dark-brown, bead-like scales with a few larger ones colored in black. Their necks are long, thick, and held straight, lifting their smaller heads up to 70 feet off the ground, nearly as high as a five-story building.

Such a size comes at a cost. Their bodies have become a haven for various parasites, latching onto their hide and draining their blood. Many animals aren't exempt from these tiny menaces, but to them, an Argentinosaurus is the world's largest all-you-can-eat buffet. All they can do on their own is to shake their bodies and rub their skin against the trees and ground. However, some Argentinosaurs lie down, resting with their head and tail curled and touching one another. As they rest their bodies, they become surrounded by and covered with a smaller type of dinosaur.

They are Overoraptors, a type of 2-foot-long, two-legged therapod closely related to modern birds. This can easily be seen in the beige feathers on their body as well as the gray ones on their head, tail, and arms. Their days are primarily spent on top of the resting Argentinosaurs, where they find their most preferred meal in massive abundance, the parasites. This creates a perfect symbiotic bond, a large supply of food for the Overoraptors, and a clean hide for the Argentinosaurs. But for the much smaller Overoraptors, it's a meal they must climb for. Once they reach the top of the giants, the feathered dwarfs simply peck at the skin of the giants, clamping down on and chewing the parasitic bugs. Whether it be ticks, lice, mites, mosquitos, or most flies, none of them are safe from the jaws of a hungry Overoraptor.

Suddenly, one of the Overoraptors picks up its head and looks toward the other side of the river. There lies a slight hill where a large animal emerges from the horizon. The Overoraptor lets out a squawk before dashing behind a laying Argentinosaurus, along with the rest of its small kin. One Argentinosaurus lifts its head as well staring at the emerging animal. As the animal steps into and starts crossing the river, its identity becomes clear.

It is a Mapusaurus, the top predator of the area. It is a two-legged carnivore reaching 40 feet in length, 12 feet in height, and weighing as much as a male elephant seal. The scaly skin of this male is primarily grayish black with a beige underbelly running from the bottom of his chin to the tip of his tail. He also has a row of red stripes running along his back and a brighter red blotch on his throat. This same brighter color is seen on a pair of bony ridges that run down from above each of his eyes until shortly behind his snout. His narrow, elongated skull is four feet in length with a jaw full of many sharp, serrated teeth. Although he is only walking at a leisurely pace, his footsteps make large splashes in the river water.

As he emerges from the river, the Argentinosaurs attempt to ward off the large predator. They do this by pulling their necks back and letting out loud creaking groans. The Mapusaurus ignores them and continues walking through the herd, all while occasionally sniffing the air. The calls of the giants dissipate as the predator passes and enters the forest behind them. As the Mapusaurus disappears into the forest, the Overoraptors pop back up, resuming their feast.

The ground of the forest is scarcely different from the land outside of it. Though the araucaria trees are more frequent and tightly packed as well as the shrubs, the ground is still just as gravelly. Light however is mostly blocked out, only showing up in small patches between the shadow of the tree canopy. Parts of the ground also sink in as the Mapusaurus walks through, creating a trail of three-toed footprints. He stops, lifts his head up, and starts sniffing the air. Thanks to having a large olfactory lobe, he has an excellent smell, one matched by a few animals that would evolve after it. The predator's sniffing ends after one extended inhaling of air before looking down to find a gray rock with a white scratch on it. He reaches his nose against the rock and sniffs it, catching the pungent scent of urine. On the ground around the rock, he also notices footprints, ones exactly like his but weren't made by him. Some footprints are much the same yet only a small fraction the size of the predator. He then brings his head back up and sniffs the air once more, this time finding a different scent altogether. The predator pauses only for a moment before strolling further into the forest.

The Mapusaurus soon finds a clearing, one with fewer trees, but covered in beige-gray pebbles and rocks as well as a small stream. He finds the source of a foul, rotting stench, a dead Argentinosaurus. This is the body of a sub-adult, but from head to tail it's still as long as a tanker truck. Its skin is faded, covered in tooth marks, and exposed dark red flesh. The chest cavity is open revealing dark-colored meat and gnawed-on rib bones surrounded by buzzing flies. But these aren't the only creatures that surround it.

The carcass is guarded by the only thing that could bring down such a giant, a pack of Mapusaurs. Four of them are 36-foot-long females with gray skin and beige underbellies, and no red coloring as seen in the males. They simply lay around the large carcass sleeping, making soft grumbles as they breathe in and out. There are also six 5-foot-long youngsters running around and snapping their jaws at each other. They are much the same as their adult counterparts in terms of male and female skin coloring but have different size proportions. Their legs and bodies are skinnier, their skulls shorter and their eyes bigger. In the center of the pack, right in front of the exposed guts of the carcass, lies the pack's alpha. It is another male Mapusaurus, this one much older with more faded red colors and a series of thin scars along his body and face. Like the females, he lies sleeping as the meat inside him continues to digest.

The intruding male lets out a growling bellow, sounding like a crocodile but with a much deeper pitch. Awakened by the noise, the alpha stands up and bellows back. The babies find shelter behind the females who are also awoken by the bellowing of the males. As they start to growl, the rival males slowly circle one another. Their footsteps cause loose twigs and branches to snap under the weight of their five-and-a-half-ton bodies.

Suddenly, the intruder charges, his jaws opening as he sprints toward the alpha. The older male quickly steps to his right and bashes his head into the side of his rival's face knocking him away. The intruder wobbles and shakes his head before bellowing at the older male. In response, the alpha bites down on the younger male's upper jaw and swings his head back and forth. The intruder bites his lower jaw onto that of the elder, causing him to let go. Tooth gashes are now visible on both male Mapusaurs, stained in their blood. They then slam the sides of their skulls together, each one struggling to push the other away to no avail. The alpha pushes his rival's head down before he shoves his right side into his left. His face pressed against the other's; the intruder repeatedly snaps his jaws attempting to bite the older male. The youngsters peer their heads from behind the adult females, watching as the younger male pushes away the alpha.

The intruder grazes his teeth against the hip of the elder leaving a deep bleeding gash. The alpha bashes his skull against the side of his rival, knocking him onto the ground. With a limp, the elder steps backward then to his right while letting out another bellow. As the alpha raises his head above him, the younger male quickly bites down on his rival's neck as he gets back up. He shakes and tussles with the older male before knocking him against a tree. The alpha abruptly drops to the ground, his eyes closing as he breathes slowly but heavily.

Standing as the victor, the intruder turns around, directing his attention to his new goal. He doesn't go to the carcass but rather toward the baby Mapusaurs. Having bested the alpha, he now has a claim to leadership of the pack and thus the right to mate with the females. But to do so, he must first kill the offspring of his rival, ensuring that the next generation will only be from the stronger male. All the females can do is step back exposing their young, as even they can't stand up to an adult male Mapusaurus. The babies chirp and quiver in place as the new alpha approaches. He lowers his head down, using his left eye to stare down at the squealing babies. The invader pulls his head back and opens his jaws, ready to bite down on his rival's legacy.

Suddenly, the elder male charges and bites down on the top of the intruder's skull. The young male temporarily breaks free only for the alpha to bite again harder and push him away from the babies. The intruder lets out another bellow before his head gets bashed into a tree, breaking it as he is sent collapsing to the ground. The alpha stands heavily panting as he stares down his knocked-down rival. He lets out a louder bellow as the younger male slowly stands back up and walks away. For a moment, the intruder stops and looks back revealing the consequence of his fight. His left eyeball is now gone. In place of it is a blood stain on his eyelids and a long gash running from the top of his skull to below his eye socket. All he has left to do is let out a huff before leaving for good. The alpha lets out one final longer bellow before lying back down with the females of his pack. His young also greet him chirping and rubbing their heads against their father. The alpha responds with a soothing rumbling noise as he doses off. No single pack alpha will ever give up leadership lightly, even if it means wounding another giant's pride.