Before penguins ruled Antarctica, dinosaurs roamed across what was then a forested continent, migrating over from Australia and other land masses that were connected to it at the time. Several Antarctic dinosaurs have already been found, including an armored ankylosaur and a handful of birdlike dinosaurs. But researchers working on James Ross Island off the Antarctic Peninsula have now reported the discovery of what may be the biggest dino yet: a fossil (inset) from the tailbone of a sauropod, a giant, four-legged dinosaur with a long neck and tail. As they write in Naturwissenschaften this week, the researchers believe this plant-eating beast lived during the Cretaceous period, which lasted until about 65 million years ago. The team can’t identify which of the 150 sauropod species the dinosaur belonged to, but it hopes to find some of his friends still buried in the frozen wasteland.