The computer-generated critters in the movie 10,000 BC—due out Friday—all actually existed at some point, but their portrayal in the film is scientifically sketchy. Saber-toothed tigers and woolly mammoths weren't as big as portrayed, and the film's huge terror birds died out 40 million years ago. One surprise accuracy, though: Ancient Egyptians might have actually been aware of woolly mammoths, LiveScience reports.
Some holdout mammoths lasted on Arctic islands until 3,000-4,000 years ago, LiveScience reports, in one of several cases where filmmakers applied poetic license to geography. Those mammoths weren't all that mammoth, however. "They had large heads, and had larger tusks than modern elephants, but their bodies were relatively diminutive," says an expert on prehistoric mammals.