The actual hypothesis that birds were descendants of dinosaurs was suggested as early as the mid-19th century by biologist Thomas Henry Huxley. However, without significant evidence, Huxley’s theory never gathered steam. It wasn’t until 1969 when John Ostrom found a theropod (a suborder of dinosaurs) which had a skeletal structure that was almost identical to modern birds. This caused a much more systematic search for fossils of feathered dinosaurs, which were eventually discovered in the mid 1990’s. Since then, it has become common knowledge amongst biologists and paleontologists that some dinosaurs were indeed feathers, and many current species of birds are their descendants.