T. rex skeleton. Credit: ScottRobertAnselmo / CC BY-SA 3.0 Scientists have long searched for dinosaur DNA, but none has been recovered. The genetic material breaks down over time, making it unlikely to survive for millions of years. Instead, researchers rely on fossils to understand how these animals lived. Now, evidence of T. Rex blood vessels preserved inside fossilized bone is offering a rare new window into dinosaur biology. Most dinosaur kn…