Big insects once roamed the US. They were very big. Ants were the size of small birds 50 million years ago. They are thought to have crossed the arctic land bridge that once existed between Europe and the US. The Green River site in Wyoming has given up many new finds in the past.
Bruce Archibald of Simon Fraser University in British Columbia noted that the fossil was similar to one found in Germany. Only the queen of theDoryluswilverthi species of ant living today reaches this size. Fittingly, the new ant has been named Titanomyrma lubei. Louis Lube found the specimen. While this ant is big for North America, big ants probably lived in other parts of the world because large fossils of other creatures have been found there.
Large ants only live a tropical climate in the present so North America was tropical millions of years ago. It is a mystery how they crossed the temperate Arctic region then. For brief periods this area became quite warm, up to 8 degrees Celsius, though not tropical. Bursts of carbon dioxide into the atmosphere from sediment was the culprit. With two sources for ancient giant ants now known it may be possible to identify where they originated.