Dino-bird debate: earth/life science.

What has feathers but isn't a bird? According to some scientists, it's a dinosaur!

Paleontologists (dino scientists) have long claimed that similarities in the skeletons of birds and some dinosaurs suggest that the animals are related. In fact, many paleontologists believe birds descended from dinosaurs.

Now, the discovery of a 121-million-year-old fossil strengthens that claim. The fossil, discovered in China last October, shows the imprint of a dinosaur with feather-like structures along its back. Before this find, birds were the only animals known to sport feathers.

Paleontologist Philip J. Currie, who has seen the fossil, says the "feathered" animal was definitely a dino and not a bird. For one thing, its arm bones were too short to support wings.

But ornithologist (bird scientist) Alan Feduccia doubts the dino really had feathers. The "feathery" imprints, he says, could have been made by some other kind of reptilian scales.

Feduccia also claims that another recently discovered fossil contradicts the bird-from-dino theory. Last year, he and a team of Chinese paleontologists unearthed a fossilized, modern-looking bird that lived some 75 million years earlier than the most birdlike dinosaurs. So those dinos couldn't have evolved into that bird, Feduccia says.

Either the evolution from dinos to birds took place earlier, or both birds and dinos evolved from some other common ancestor. In either case, the feud over feathers rages on.

Scientists will study both fossils -- and other ones -- more carefully before they finally resolve their differences ... maybe.