Albertosaurus vs Chriostenotes
We find ourselves in southeastern Alberta, around 71 million years ago. This location will one day be the middle of the Horseshoe Canyon Formation, exposed as badlands rock along the Red Deer River. Now, it’s a temperate, misty coniferous forest, with huge redwood trees stretching out over a spongy forest floor covered in ferns and rotting logs. This woodland is home to a variety of creatures, from opossum-like mammals clutching to tree branches, to soft-shelled turtles lounging in shrinking ponds, to a variety of dinosaurs large and small.
On the outskirts of the forest, a herd of Hypacrosaurus, a type of crested duckbill, have been feeding on the soft, rotting bark of old fallen logs. Suddenly a large Albertosaurus, this ecosystem’s top predator, lunges out of a thicket with a sudden burst of speed. She quickly seizes one of the Hypacrosaurus by the neck, crushing the vertebrae in her jaws. She then dragges the carcass deep into the woods while the rest of the herd flees, bellowing in panic.
In a small clearing, the Albertosaurus now starts to feed on her catch. However, her success has not gone unnoticed. The smell of freshly killed hadrosaur has attracted other Albertosaurus from all over the area, who follow their acute sense of smell to track the kill.
Soon nearly a dozen of the large carnivores are cautiously approaching the scene (Eberth & Currie, 2010). The Albertosaurus who made the kill doesn’t want to share. She puffs up her throat and hisses with her jaws gaping open in a threat display, showing off her teeth. This doesn’t deter the other tyrannosaurs, who start to inch closer.
Meanwhile, the birdlike caenagnathid Chirostenotes is wandering through the woodland, nipping at flowers and tender leaves as it goes. He’s been transported here from the earlier Dinosaur Park Formation, and while this ecosystem is a bit cooler and drier than he’s used to, Chirostenotes isn’t uncomfortable. Bobbing his head as he goes, Chirostenotes wanders up a dried-out riverbed, leaving three-toed tracks in the mud.
Back at the Albertosaurus clearing, things are escalating. More Albertosaurus have arrived, ranging from lanky teenagers to scarred, bulky adults. The predators are becoming more and more intolerant of each other, and open-mouthed threats turn to guttural sounds and snapping at one another. A bold subadult gets one step too close to the hadrosaur carcass, and the Albertosaurus who originally made the kill has had enough. She lunges forward and snaps at the younger animal, her jaws clapping together in a deep thud, just missing the intruder’s neck.
This display of aggression triggers the other Albertosaurus to rush towards the carcass, jostling to grip hold of a piece of flesh, which they intend to tear off and run away with. Our first Albertosaurus, still not satisfied with her dinner but not yet willing to sacrifice her own safety, turns and trots away from the scene, bristling with frustration.
Our Albertosaurus arrives at the dried riverbed, and follows along, hoping to run into something that will help satiate her awakened hunger. Suddenly, she spots movement several meters down. The Chirostenotes has unwittingly walked into a patch of deep, thick mud. He tries to wade through with his long, skinny legs, but the muck pulls stronger as the dinosaur struggles, and sticks to his matted feathers (Funston, 2020).
This creature will satisfy the Albertosaurus’ appetite nicely. With a few strides of her long legs, the Albertosaurus easily covers the distance down the riverbed. She snatches the mired Chirostenotes in her crushing mouth. The Albertosaurus shakes her prey from side to side like a giant dog. Chirostenotes now hangs limp and lifeless from the predator’s jaws, soon to disappear down the gaping throat.