strangest prehistoric creatures to rule the earth

The TRex pales in comparison to the massive but lesserknown Spinosaurus. Reaching up to 59 feet (18 m) long, this prehistoric beast could weigh more than a semitruck and the webbed spines on its back could have easily reached the height of a basketball player. Spinosauruss alligatorlike mouth likely means it was a major fish eater and spent much time in the water. Makes us wonder whether those back spines could have been used for swimming.