Almost 50 million years ago, ants the size of hummingbirds roamed what is now Wyoming, a new fossil discovery reveals. These giant bugs may have crossed an Arctic land bridge between Europe and North America during a particularly warm period in Earth's history. At about 2 inches (5 cm) long, the specimen is a "monstrously big ant," said Bruce Archibald, a paleoentomologist at Simon Fraser University in British Columbia who reported the discovery today (May 3) in the journal Proceedings of the Royal Society B. Though fossils of loose giant ant wings have been found before in the United States, this is the first known full-body specimen.