One of my good online friends happens to be a dinosaur. Not just any dinosaur a Tyrannosaurus rex. he may be pint-sized, but he is extremly smart and a the best theropod ("beast-feet") that I know. As a tribute ot his good will and good work on his blog (http://traumador.blogspot.com/), I will give his species some more fame.
Every one knows this infamous carnivore. Discovered by Barnum Brown in the early 20th century, T-rex has been the star of most dinosaur movies in the past century. However, it has been mostly characterized as montser that mindlessly eats anything in it's path. That is WRONG!!! It was amazing and fearsome, yet, it was an animal that had the same basic needs as animals (like us) do today.
It's closest living reletive today would be the birds. T.rex was very similar to a modern bird. Even though it grew up to 18-20 feet tall, weighed 6-7 tons, and grew to at least 40 feet long, it's bones were hollow, yet, strong. It had bone-crushing teeth with serrations on both sides, as big as a banana. Like modern birds, T-rex had a backward pointing joint. (It's ankle was pointed backwards, as in birds, their knee points backwards.)
It's been theorized by Paleontologists as fierce predator and/or scavenger. Nevertheless, it was well muscled and had a large olfactory lobe (that's the part of the brain that controlled an animal's sense of smell, and it had one of the largest in the fossil record.)
Prey animals may have included ceratopsians like Triceratops, and Torosaurus, and duck-billed hadrosaurs (eg. Parasaurolophus, Maiasaura, Corythosaurus, etc.).