Eotriceratops vs Albertosaurus
The wind blows wildly over the Western Interior Seaway, creating whitecaps on the billowing blue waves. It is 84 million years ago, in what is now Kansas. Much of the interior of North America is under this deep, vast seaway. The waters are teeming with fish and ammonites, which in turn are preyed upon by sharks and other large fish, turtles, diving birds, and giant marine reptiles. Overhead, small gull-like birds and large pterosaurs with elaborate crests circle above the water, screeching in the blinding sunlight.
Out of nowhere appears two dinosaurs from the drier redwood forests of late Cretaceous Alberta. Eotriceratops and Albertosaurus are thrust into this marine world. Normally these two would behave in a typical predator-prey relationship, but finding themselves suddenly immersed in deep salty water, they now have to work just to stay alive.
Albertosaurus sits low in the water, her head and the top of her back and tail exposed at the surface. With her internal air sac system and hollow bones, Albertosaurus is lighter than she looks, and manages to keep afloat and able to breathe. She notices the Eotriceratops nearby, but leaves the giant ceratopsid alone- this is no time to go after food. She also notices a string of sandy islands on the eastern horizon. Any kind of land is better than this.
Kicking with her strong hind legs, Albertosaurus is able to make a crude yet effective attempt at swimming (Xing et al., 2013). As she paddles, she resembles a bizarre mix between a giant water bird and a crocodile. Beneath her, the dark shapes of fish criss-cross below the waves, some of them approaching the length of Albertosaurus herself. However, these underwater shapes aren’t making for the paddling tyrannosaur.
Eotriceratops has not fared nearly as well in the deep water. His enormous skull, dense skeleton, and thick, scaly skin cause him to sink head-first like a rock (Henderson, 2014). In much shallower water he could have easily punted himself up to the surface to breathe, and then along the bottom to the nearest shore, much like a modern hippo. However, this water is far too deep for that. Despite his thrashing struggles, Eotriceratops keeps slipping below the surface. Large ichthyodectid fish and a variety of sharks are drawn in by his splashing.
Eotriceratops soon grows tired, and can no longer stay above the waves. He succumbs to drowning, as his body is picked at by a variety of marine scavengers. Soon, the enormous dark shape of a Tylosaurus glades in like a giant phantom, and makes off with the carcass.
These distracted predators ignore Albertosaurus who, thirsty and uncomfortable, makes her way closer and closer to dry land, managing to live another day.