How did birds first take off?

Stephen Brusatte, then 9 years old, was inspired by 'Jurassic Park.' In 1993 he decided to become a Paleontologist. Brusatte, a paleontologist since 1993, was delighted to give advice to the producers of 'Jurassic World: Dominion.'

He was particularly happy to see dinosaurs with feathers on the screen, as this was one of his most important discoveries. According to the emails he's been receiving, not all moviegoers share his enthusiasm.

Professor Brusatte at the University of Edinburgh said that a lot of people believed it to be fabricated. They thought that filmmakers were trying to make something crazy.

Michael Rothman provided an illustration of the artistOs impressions of distant relatives of birds of today that dominated Mesozoic skies about 125 million ago: Male Feitianius (6); female Feitianius (5); Orienantius (4); center Sulcavis (7); Avimaia (1); Falcatakely (3); and Longipteryx (2). Scientists say it took feathered dinosaurs 150 million years to learn how to fly and develop into the birds that we see today. (Michael Rothman, via The New York Times).

Feathered dinosaurs are not a myth. They have been well established thanks to the remarkable fossils found in northeast China from the mid-1990s. Now Brusatte, along with other paleontologists, are trying to figure out how feathered dinos evolved into the birds we see today. This evolutionary mystery spans more than 150 millions years.

In 1861, quarry workers from Solnhofen in Germany discovered a fossilized bird that was 145 million years old. It was named Archaeopteryx. Charles Darwin was thrilled. He had published a book called 'On the Origin of Species" two years before. Archaeopteryx resembled what Darwin would have predicted had birds evolved from reptilian origins. He told a friend that it was a great case.

Archaeopteryx, however grand it may have been, did not solve the case. The study did not reveal, for instance, which reptiles evolved into birds or how they developed wings.

Researchers from the DU find more than 250 dinosaur eggs in central India. What do they observe?

John Ostrom was a Yale University paleontologist who, in the 1970s identified similarities between the skeletons and birds of theropods (a group which includes the Velociraptor, Tyrannosaurus Rex, and others). No theropod fossils, including feathers or wings, were preserved. Ostrom and his colleagues argued about the origins of birds for years without more evidence.

Pei-ji, a Chinese paleontologist, from the Nanjing Institute of Geology and Paleontology, attended a meeting of paleontologists at the American Museum of Natural History, New York. He gave Ostrom a package of photos.

The images showed a fossilized dinosaur with what appeared to be primitive feathers. Ostrom was so shocked that he had no choice but to sit down.

Sinosauropteryx Prima, a 125 million-year-old dinosaur fossil from northeastern China's Liaoning Province, was discovered in the province. The fossil was preserved beautifully in a blanket of ash that looked like Pompeii. Since then, the region has produced a constant stream of dinosaur feather fossils.

Brusatte stated that there are thousands of feathered dinosaurs now.

Paleontologists discovered that feathers weren't only found in theropods. Some species had feathers that looked like simple wires, rather than the complex interlocking filaments of modern bird feathers.

Paleontologists suspect that feathers were present in the dinosaur ancestor. Recent discoveries suggest that feathers existed before dinosaurs.

Pterosaurs were the closest relatives to dinosaurs. They flew like bats, with membranes that stretched from their hands down their sides. They also had feathers.

Initially, the first feathers could have been used as insulation. It is possible that the largest dinosaurs were able to use their large bodies to retain warmth, which may be why they seem to have lost their feathers.

Theropods had feathers that were more complex. Some feathers resembled fluffy down. Some evolved feathers with complex patterns that could be arranged into sheets - the first wings. Early Theropods were unable to fly with their wings. Some species of horse-sized animals had wings as large as laptop screens. Brusatte hypothesized that dinosaurs would use these elaborate feathers to display their courtship.

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Theropods exploded in bizarre feathered forms by 160 million years ago. Julia Clarke and her team of paleontologists from the University of Texas studied fossils of an incredibly bizarre and stunning species named Caihong Juji that were discovered in Hebei Province, China. Fossilized feather pigments indicate that the body of this bird was black while its head, shoulders and tail were iridescent.

Caihong Juji's feathers are difficult to understand. Modern birds have asymmetrical wing feathers that help direct the air flow to create lift. Caihong Juji, however, had only asymmetrical feathers on its tail.

Theropods could have used their feathers at first to create lift when they ran. This ability may have enabled them to scale trees or climb steep slopes more quickly. Caihong Juji, a feathered dinosaur that lacks the muscles to fly like birds but could have glided and jumped in ways scientists are still trying to discover.

Jingmai O'Connor is a paleontologist working at the Field Museum, Chicago. She said, "These organisms seem to defy logic."

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Feathered Dinosaurs were not just intermediates in the evolution of birds. They lived for tens and millions of years. Clarke stated that 'they were clearly good at what they were doing'.

Archaeopteryx was a branch of dinosaurs that evolved to be able to fly farther distances. Paleontologists disagree on how well Archaeopteryx could fly. Archaeopteryx possessed asymmetrical feathers, but it lacked a sternum to anchor its powerful flight muscles.

Approximately 130 million years later, the early birds split in two branches. Both evolved independently to become powered flyers. Ornithuromorphs is the name of the lineage which led to all current birds. The enantiornithines were the branch that dominated for tens and millions of years.

Enantiornithines are similar to birds in appearance. O'Connor, along with her colleagues, are revealing a strange biology in them.

Birds, for instance, are usually born with no feathers, or only a fuzz of down, but they grow feathers all over their body. As adults, they molt their feathers gradually so that they don't lose the coat which keeps them warm.

In a recent paper, O'Connor and colleagues argue that enantiornithine feathers developed in a completely different manner. The enantiornithine birds hatched without feathers on their bodies, but had fully feathered wing. They developed plumage as they matured. As adults, their feathers molted all at once. They had to live without their plumage until their new feathers developed.

A large asteroid hit the Earth 66 million year ago. About three quarters of the species on Earth were destroyed, including all feathered dinosaurs except for the ornithuromorphs.

O'Connor, along with other paleontologists, are trying to determine why these birds survived while all other feathered creatures vanished. Dinosaurs with feathers who ate small animals or leaves may have died from starvation. Birds had evolved beaks which allowed them to consume the huge quantities of seeds that were buried underground.

O'Connor believes that other factors could have been involved. The enantiornithines, who had thrived for 70 million or more years before the asteroid hit, may have become vulnerable when they all molted at once.

O'Connor stated that if you throw them into an impact winter where global temperatures are now lower and there is a resource shortage, this will push them to the edge.

The original version of this article appeared in The New York Times.