In 1963, what John Ostrom, an American paleontologist, discovered was a claw, obviously goes to a foot, but not for walking on. Deinonychus was small with a delicate build and was an active predator that clearly killed its prey by leaping and slashing or stabbing with its “terrible claw”. It ran upright on two legs. It had a long stiff tail for balance. He saw that they both had lightly-built, hollow bones. And they shared even more features, including long arms and similar hip and shoulder bones. Ostrom concluded that birds did descent from dinosaurs as Huxley had argued.
Not from lumbering sauropods, but from another lineage called theropods that walked on two legs and included T. Rex, and agile predators like Deinonychus.
Look at T. Rex foot, what we see are three forward-facing digits that bear the weight of the animal, and in the back, a much smaller digit. If we take a look at a chicken foot, we see the same pattern. An S-shaped neck of dinosaurs is also seen in living birds like chicken.
Supporting evidence continued to accumulate including the discovery that theropods had a feature of birds not previously found – a wishbone. When scientists analyzed the skeletons of theropods and birds, they found too many similarities for any explanation but common ancestry.
In the mid-1990s, farmers in northeast China began unearthing dinosaurs 120 million years old. This chicken-sized theropod did not have scales. It was covered in some primitive kind of feather.
With the discovery of more feathered finds, there was no longer any doubt that birds were related to theropods. But these animals could not fly. Why were they feathered? Why did the first feathers evolve?
(To be continued) (Floro Mercene)