Tyrannosaurus was possibly the largest land carnivore ever. While the exact size of Tyrannosaurus is hard to determine, a fully grown adult was probably about 40-43 feet in length and weighed as much as 6-9 tons. Despite it's massive size, Tyrannosaurus could run between 15 and 25 miles per hour. They may have been pack hunters and probably worked together to raise the young. Young Tyrannosaurus' likely had a covering of feathers while adults may have had a few feathers as well. Tyrannosaurus may have had a bite force of up to 3-20 or more tons per square inch depending on the estimate and had teeth up to 13 inches long! Tyrannosaurus was potentially the most powerful land predator ever. They lived 65-68 million years ago in western North America.