In nature today, predatory animals are very cautious about who they attack.
For instance, a single lion will rarely, if ever, take on an animal as big as a water buffalo.
Now a pride of lions will certainly do it, but a lone lion usually won't, unless they are in desperate need of food.
Attacking something that can defend itself is not in the best interest of the attacker.
So Utahraptor probably saw Gastonia on a daily basis, but it would think twice about attacking one unless it had no other choice.
The Utahraptor would normally have jumped on its prey's back, but against the armor plated Gastonia, that would be futile.
A fight between these two animals could have happened a thousand different ways.
There are just too many variables to consider.
So when we recreate a scenario, we try to use as much evidence and scientific fact as possible.
We study the prehistoric environments.
We study the skeletal design of the dinosaurs, and then other evidence, so we can paint a realistic picture of what could have occurred.
It's a combination of these factors, that allows us to pose a realistic representation of what could have occurred.
The work from initial discovery to excavation and cleaning, reassembling and final analysis can take tens of thousands of man hours.
But the resulting hypothesis are invariably fascinating.
This dry, desolate riverbed is the result of a major drought.
A lone Gastonia walks with his head hovering above the ground.
He's trying to sniff out water for survival.
His vision is poor, so his entourage of Pterosaurs acts as lookouts for predators.
His incredible sense of smell tells him there's water just underneath the soil.
Using his front legs, the little Gastonia begins to dig.
It won't take much to get to the water below.