Much as last week's announcement about giant fossil spiders, we have to take the word "giant" in context.  Paleontologists revealed today that the have found giant ant fossils--giant when compared to today's ants.  Modern-day giant ants are around an inch long, but this fossil was from about 50 million years ago, and was at least two inches long, making this ant, Titanomyrma lucei, about the size of a hummingbird (see photo).  Found in the Green River section of Wyoming, these ants were most likely living in a region whose temperatures were tropical, based on the habitat preferences of today's giant ants, which reside in South America, Southeast Asia, and Australia.  Wyoming was extremely warm in those days, and scientists are debating if T. lucei traveled from there to other parts of the world or if they migrated here from Asia via the Siberian land bridge that connected Russia and North America at a time when there was a cycle of advancing glaciers alternating with warm times.  As we find out more about these ants, we may get to answer that question, just like we did for elephants and camels which once roamed the west coast of the Americas.