Dinosaurs are a group of reptiles that first appeared about 245 million years ago. They dominated the planet until an extinction event wiped out a large swath of life on Earth about 66 million years ago. But now we know that the Age of Dinosaurs never ended. Instead, a group of dinosaurs gave rise to a new, small airborne form: birds.

What can you learn about ancient creatures from the fossils they have left behind? Find out how scientists discover millions-of-years-old dinosaur fossils in the field, bring them back to the Museum, and study them in the laboratory. In this Google Virtual Field trip, renowned paleontologist Mark Norell leads a behind-the-scenes tour of the Museum Paleo Prep Lab. This is where real discoveries are made, as experts extract fossils from rock and examine the evidence to determine what kind of dinosaur it was and how it might have lived.

The oldest evidence of the dinosaur lineage—fossilized tracks—was desribed in Proceedings of the Royal Society B. Just one or two million years after the massive Permian-Triassic extinction, an animal smaller than a house cat walked across fine mud in what is now Poland.

Dinosaur fossils are found almost exclusively in sedimentary rocks, which form when sand, silt, mud, and organic material settle out of water or air to form layers that are then compacted into rock. Paleontologists look for fossils in sedimentary rocks that were deposited on the continents, primarily by rivers and streams, or in lakes into which the streams emptied. Occasionally, dinosaur fossils are also found in sedimentary rocks representing ancient, desert sand dunes. The sedimentary rocks must have been formed or deposited during the Mesozoic Era, the geologic time period when nonavian dinosaurs lived. 

Paleontology Collections Manager Carl Mehling gives us a behind-the-scenes tour of the Big Bone Room, which houses some of the largest items in the Paleontology collection. Its holdings include one of the largest complete limb bones in the world: the 650-pound thigh bone of the long-necked, plant-eating dinosaur Camarasaurus. More than 3 million specimens make up the Museum's world-class paleontology collections, and only a small fraction can be displayed at any given time. The rest are stored behind the scenes, where they continue to be studied by Museum scientists and their colleagues.

A pigeon-sized, four-winged dinosaur known as Microraptor had black iridescent feathers when it roamed the Earth 130 million years ago, according to research led by a team of American and Chinese scientists that includes Museum researchers. The dinosaur’s fossilized plumage is the earliest record of iridescent feather color. The findings, which suggest the importance of display in the early evolution of feathers, are published in the March 9, 2012 edition of the journal Science.

One of two halls in the David H. Koch Dinosaur Wing, the Hall of Saurischian Dinosaurs displays fossils from one of the two major groups of dinosaurs. Saurischians are characterized by grasping hands, in which the thumb is offset from the other fingers. This hall features the imposing mounts of Tyrannosaurus rex and Apatosaurus.

Dinosaurs might have survived the asteroid strike that wiped them out if it had taken place slightly earlier or later in time, according to research conducted in part by the American Museum of Natural History. The study, published in July 2014, Biological Reviews, builds a new narrative of the prehistoric creatures’ demise some 66 million years ago when a six-mile- (10-kilometer-) wide asteroid struck what is now Mexico.

The extinction of non-avian dinosaurs holds a stubborn place in our imagination, but in reality dinosaurs never vanished from the Earth. Much of the work understanding the evolution of modern birds is being done by scientists working or trained at the Museum, including Dr. Amy Balanoff, whose work compares the brains of ancient dinosaurs and modern birds.

Were dinosaurs already undergoing a long-term decline before an asteroid hit at the end of the Cretaceous about 65.5 million years ago? A new study led by Museum scientists gives a multifaceted answer.

Richard Gilder Graduate School (RGGS) doctoral student Shaena Montanari uses her geology training and subtle clues left by dinosaurs to reconstruct the environment of Mongolia’s Gobi Desert as it was 70 million years ago. Based on an innovative approach that takes cues from the geochemistry of dinosaur eggshells, Montanari’s latest findings—that late in the Mesozoic “age of the dinosaurs” the Gobi desert was a much wetter and warmer place than today—were presented at a poster session of the American Geophysical Union’s Fall Meeting in San Francisco.

Recent research clips the wings of Archaeopteryx. First found in Germany in the 1860's and dating to 150 million years ago, Archaeopteryx has long been considered the iconic first bird. But microscopic imaging of bone structure published in PLoS One shows that this famously feathered fossil grew much slower than living birds and more like non-avian dinosaurs. The bones of more recently discovered bird fossils like Confuciusornis, a primitive but toothless bird from the Yixian Formation in China that appeared after Archaeopteryx, demonstrate rapid growth more similar to that of modern birds. This means rapid bone growth — long thought a prerequisite for flight — was not necessary for taking to the air.

By describing a new double-clawed and highly-unusual relative of Velociraptor, paleontologists have answered a long-standing question: what did the Late Cretaceous predatory dinosaurs in Europe look like? Balaur bondoc, described this week in Proceedings of the National Academy of Sciences, is the first reasonably complete skeleton of a meat-eating dinosaur from the final 60 million years of the Age of Dinosaurs in Europe and provides insight into an ecosystem very different from that of today.

Who would travel halfway around the world to spend the summer in a desert where brutal sandstorms and surprise flash floods are on the itinerary? Meet Mike and Mark, who've made the trek annually since 1990. 

In an evolutionary sense, birds are a living group of dinosaurs because they descended from the common ancestor of all dinosaurs. Other than birds, however, there is no scientific evidence that any dinosaurs, such as Tyrannosaurus, Velociraptor, Apatosaurus, Stegosaurus, or Triceratops, are still alive. These, and all other nonavian dinosaurs became extinct at least 65 million years ago at the end of the Cretaceous Period.

Many, shared, evolutionary characteristics can be found in the skeletons of birds and other dinosaurs. One can follow the development of these evolutionary innovations by following along the evolutionary tree of dinosaurs from larger groups into successively smaller ones.

Sauropods dominated Earth for 140 million years. How did they reach their massive sizes? What did they look like, how did they move, and what did they eat? Enter the lab to discover the answer first hand. 

Since 1990, Museum scientists have traveled to Mongolia to find fossils, continuing a tradition of Museum expeditions to the area since the 1920s. Last summer, a team led by Provost of Science Mike Novacek and Paleontology Division Chair Mark Norell headed to the Gobi Desert. The group included Aki Watanabe, one of Norell's students at our Museum's Richard Gilder Graduate School, who is a beta-tester for Google Glass and who recorded video on Glass during the trip.

Travel with the team to the heart of Mongolia in the first video of this series.

Mixed graveyards filled with exceptionally well-preserved dinosaurs, mammals, early birds, fish, and reptiles in northern China are the result of lethal volcanic flows, according to new work by an international team of geologists and paleontologists, including Museum Curators Jin Meng and George Harlow. The finding helps unravel the mystery behind the preservation history of the Jehol Biota—an ancient ecosystem that existed between 130 to 120 million years ago. The research is published today in Nature Communications.

New research shows that dinosaurs evolved bird-like brains well before they took to the air as birds. Museum Curator Mark Norell, a paleontologist, and Research Associate Amy Balanoff discuss the cutting-edge techniques that have illuminated these evolutionary histories.

The Museum's Division of Paleontology seeks to describe the diversity of extinct invertebrates and vertebrates and explore the mechanisms driving their evolution and extinction. In fulfillment of this objective the Department collects, maintains, and researches specimens of fossil and subfossil invertebrates and vertebrates, and the data associated with these specimens, aiming always to provide the highest standards of curatorial care, and to promote and assist access to the collections by bona fide scholars.

Discovering a dinosaur is just the first step. Paleontologists Sterling Nesbitt, Mark Norell, and Danny Barta tell the story behind the Museum's treasure trove of Triassic fossils from Ghost Ranch, New Mexico.

The Museum’s dinosaur mummy is a fossilized imprint of the carcass of a duck-billed dinosaur. One of the most complete pieces of Mesozoic dinosaur remains ever found, this fossil represents one of the greatest discoveries in the history of paleontology.

This animal’s skin, marked by bumps called tubercles, was similar to the skin on bird feet. The tubercles are larger along the animal’s back and sides and smaller around the joints, which needed to be flexible.

A new species of feathered dinosaur discovered in southern Germany is further changing the perception of how predatory dinosaurs looked. The fossil of Sciurumimus albersdoerferi, which lived about 150 million years ago, provides the first evidence of feathered theropod dinosaurs that are not closely related to birds. The fossil is described in a paper published today in the Proceedings of the National Academy of Sciences by researchers at the Museum and at the Bayerische Staatssammlung für Paläontologie und Geologie and Ludwig Maximilians University, both in Germany.

Theropods are bipedal, mostly carnivorous dinosaurs. In recent years, scientists have discovered that feathering was present on many extinct theropods, but only on those that are classified as coelurosaurs, a diverse group including T. rex and birds. Sciurumimus—identified as a megalosaur, not a coelurosaur—is the first exception to this rule. Because the new species sits deep within the evolutionary tree of theropods, the findings suggest that all predatory dinosaurs might have had feathers.

Looking at the family tree of birds, there are three important aspects to keep in mind: Early birds like Archaeopteryx are extremely similar in anatomy to advanced non-avian dinosaurs like Velociraptor. For example, both had long bony tails and teeth. Early in bird history, there were flying birds and non-flying birds. This great variety of forms included flightless diving animals like Hesperornis and small active flyers like Apsaravis. Birds, with many of the advanced features we consider to be characteristic of modern birds, lived at the same time as the non-avian dinosaurs.

Reptile skin is a complex system of scales separated by flexible joints, which are identical to scales, except thinner. In birds, the only living group of dinosaurs, the scales are modified into feathers, except around the feet and beak. So, the hind feet of extinct dinosaurs probably looked like a bird’s foot, but what about the rest of their body?

One of two halls in the David H. Koch Dinosaur Wing, the Hall of Ornithischian Dinosaurs features fossils from one of the two major groups of dinosaurs. The ornithischians are characterized by a backward-pointing extension of the pubis bone, which is thought to have helped to support the enormous stomachs that these dinosaurs needed to digest the masses of tough vegetation they ate.