Quetzalcoatlus northropi

Imagine a flying reptile the size of a two-seater plane! That's Quetzalcoatlus, one of the largest flying animals ever. In 1971, a geology student discovered it in Texas. But the only remains found were parts of one wing. Paleontologists pieced together the wing one chunk at a time, starting with a massive arm bone. They think Quetzalcoatlus had extremely long legs, neck, and jaws. On the ground, it may have stood about 16 feet (5 m) tall!

Image credits: main image, © AMNH 2014; Mark Norell: AMNH.