IMAGE by Buck Denton. Sue, the Tyrannosaurus rex at the Chicago Field Museum. Sue is the largest and most complete Tyrannosaurus rex fossil skeleton. Sue is named after her founder. The sex is unknown.

Birds are the closest relatives to Tyrannosaurus rex. This information was determined by analyzing protein from T. Rex tissue that is apparently the “real deal after all” after some skepticism. Bird and reptile proteins were compared to the proteins from T. Rex ’tissue’ found during a 2003 discovery. From NPR’s All Things Considered:

Scientists are puzzled by the purported discovery of something they thought couldn’t possibly still exist — bits of soft tissue from a Tyrannosaurus rex. Fossil-hunters found the matter two years ago, and skeptics have challenged its authenticity. But now there’s new evidence suggesting the tissue is the real thing.