Tyrannosaurus Rex, the most famous dinosaur, was widespread through out North America. Tyrannosaurus was one of the largest terrestrial carnivorous dinosaurs ever, but whether it was an active solitary or pack hunting predator or just an opportunistic scavenger is a subject of much debate.
The animal's hips and legs seemed to indicate that Tyrannosaurus may have been no more than a slow runner or just a walker, only able to take small, clumsy steps. Calculations have also shown that the animal's height and weight were so great that if it fell while running, the impact would have been enough to break it skull and ribs. The tiny forearms would not have broken the force of impact.
There is little direct evidence to support this notion, however, and considerable evidence to demonstrate that T-Rex could have hunt and kill other animals. For example, a duckbilled Edmontosaurus skeleton from Montana bears a wound at the base of its tail that matches the shape of the mouth of an adult Tyrannosaurus. What is interesting is that this wound had healed over, indicating that the hadrosaur was alive during and after the time T-Rex bit into it. Paleontologists concluded that this fossil about how T-Rex hunted living animals. But as a solitary predator or hunted in packs?
How social was T-Rex? Fossil discoveries show that groups of different individuals of various ages of Albertosaurus and of Tyrannosaurus at least sometimes lived together, because they were buried together. It may be that T-Rex, and maybe some of their relatives, hunted in family packs like modern day wolves and lions. Some scientists suggest that the faster young T-Rexes could have chase their prey toward the waiting jaws of their powerful parents. Even if they did live together, T-Rex wouldn't always get along.
If you look at the cast of the brain, T-Rex have had a huge olfactory lobe, meaning that Tyrannosaurus had a tremendous sense of smell. Aided by its keen scent of smell, Tyrannosaurus may have scavenged from the bones of animals that were already dead. Being the largest predator of its time, it was able to scare away other feeding animals and dine on its stolen prey in peace, unless disturbed by another, larger Tyrannosaurus. However, scientists have noted that a good sense of smell could also be used to detect live prey as well as for behaviors unrelated to food acquisition.
I would accept that T-Rex was both a pack hunting predator and an opportunistic scavenger like most large carnivores. Because I don't think there's any evidence of T-Rex being a solitary hunter. And when someone should come up with that evidence, I don't think we should say it.