Bruce is a Tylosaurus pembinensis and is the Guinness World Record holder as the largest publicly displayed mosasaur. Bruce lived during the late Cretaceous period, approximately 80 million years ago. He swam in a relatively shallow sea environment in a very rich life environment. This ocean is termed the Western Interior Seaway and split up North America in two. The Seaway spanned from the frigid waters of the Arctic Ocean to the warm currents of the Gulf of Mexico. Bruce belonged to a group of Mosasaurs called the tylosaurines. These tylosaurines were the largest of the mosasaurs, Bruce being the largest in the world for this time period, at more than 13 meters in length or approximately 43 feet long from snout to tail. Bruce was a fierce predator at the top of the food chain in the Seaway, eating anything it its path from plesiosaurs to ammonites. The tail of Bruce is exceptionally long, moving side to side to propel him forward with snake-like undulations, while the large flippers primarily steered. Palaeontologists think the mosasaurs lineage was branched off from a lizard group know today as the Monitor Lizards.