Hesperornithoides miessleri was a feathered dinosaur with many features we now associate with birds.

Discovery of Raptor-Like Dinosaur Adds a New Wrinkle to the Origin of Birds

A small, 150 million-year-old dinosaur unearthed in Wyoming ran on the ground, but it may have been closely related to some of the first fliers

An artist’s rendering of ancient Arctic hyenas belonging to the genus Chasmaporthetes. A new study reports that two enigmatic fossil teeth found in Yukon Territory in Canada belonged to Chasmaporthetes, making the teeth the first known fossils of hyenas found in the Arctic.

Prehistoric Hyena’s Teeth Show Bone-Crushing Carnivore Roamed the Arctic

The only hyena to live in North America, <i>Chasmaporthetes</i>, had the stature of a wolf and the powerful jaws of its modern relatives

The sequoia tree slab is an invitation to begin thinking about a vast timescale that includes everything from fossils of armored amoebas to the great Tyrannosaurus rex.

A 16-Million-Year-Old Tree Tells a Deep Story of the Passage of Time

To explain the exceedingly long life of the planet, the Smithsonian’s new fossil hall designers began with this arboreal wonder

Towering over the Fossil Hall is the plant-eating sauropod Diplodocus, which has been on display since 1931 and now is posed with tail in the air.

Amid All the Fossils, Smithsonian's New Dinosaur Exhibition Tells the Complex Story of Life

The much-anticipated exhibition is packed full of Mesozoic dinosaur drama, new science, hands-on discoveries and state-of-the-art museum artistry

Reconstructed color patterns of Sinosauropteryx based on the pigmentation of fossil plumage. The dinosaur is portrayed in the predicted open habitat in which it lived around the Jehol lakes, preying on the lizard Dalinghosaurus.

The Colors of Dinosaurs Open a New Window to Study the Past

Old fossils and new technology are coloring in life’s prehistoric palette

Life reconstruction of the bizarre membranous-winged Ambopteryx longibrachium.

Newly Discovered Bat-Like Dinosaur Reveals the Intricacies of Prehistoric Flight

Though <i>Ambopteryx longibrachium</i> was likely a glider, the fossil is helping scientists discover how dinosaurs first took to the skies

A partially exposed, 65-million-year-old fish from the Tanis deposit in North Dakota.

Fossil Site May Capture the Dinosaur-Killing Impact, but It’s Only the Beginning of the Story

The Tanis site in North Dakota contains evidence of the asteroid impact that killed off the dinosaurs

The Cambrian Period was a time of remarkable diversification of life when many of the animal groups that exist today first appear in the fossil record.

Fossil Treasure Trove of Ancient Animals Unearthed in China

The fossils from the Cambrian Period include dozens of new species and provide a window into life more than 500 million years ago

Fossilized bones from the distant past and the bones that constitute our skeletons today are perhaps the best tool to help scientists learn about the evolution of life.

How Bone Connects Life's Past, Present and Future

A new book dives into the history of osteology, the study of bones, and everything we can learn from the skeletons life leaves behind

By analyzing fossilized vomit and droppings, scientists have determined that Smok wawelski was one of the first predators to crush the bones of its prey.

Prehistoric Crocodile Cousin Crushed the Bones of Its Prey Long Before T. Rex

Fossilized feces filled with bone reveal the feeding habits of an ancient predator

With just two rows of teeth, Edestus slid its lower jaw to slice apart its prey.

Scientists Model How Prehistoric Shark Cut Through Prey With 'Scissor Jaws'

The 330-million-year-old species <i>Edestus</i> had one of the most unique bites in natural history

An illustration showing what Galagadon would have looked like in life, swimming along the river floor.

New Prehistoric Shark Species Discovered Alongside Sue the T. Rex

The teeth of <i>Galagadon nordquistae</i> were discovered in the rock that once surrounded the famous <i>T. rex</i> skeleton.

The species Orobates pabsti represents a group of animals that lived after the first animals to walk on land but before the evolution of modern lizards.

Scientists Used a Robot to Study How Prehistoric Lizards Walked

OroBOT, a robot version of an ancestor to the dinosaurs, is helping fill in some gaps in the evolution of walking

Illustration of an adult and juvenile ankylosaur.

Armored Dinosaurs Kept Cool With a Labyrinth of Nasal Canals

A fluid dynamics study suggests the large and intricate passages in ankylosaurs' skulls were a great way to cool off in the Cretaceous

Although the asteroid strike that created Chicxulub crater in modern-day Mexico dramatically affected life on Earth, the fiery crash isn't the whole story of the fate of the dinosaurs.

We Still Don’t Know Why the Reign of the Dinosaurs Ended

The asteroid strike on the Yucatán Peninsula 66 million years ago is only part of the story

Ichthyosaurs (Greek for "fish lizard") were large marine reptiles that lived alongside the dinosaurs during most of the Mesozoic era.

Like Whales and Dolphins, Prehistoric 'Fish Lizards' Kept Warm With Blubber

A new analysis of a pristine ichthyosaur fossil reveals that the prehistoric marine reptile had a layer of insulating fatty tissue

The marsupial lion (Thylacoleo carnifex) stalked Australian forests tens of thousands of years ago.

How a Changing Climate May Have Killed Off the Marsupial Lion

The fearsome predator, related to koalas and wombats, ruled the wilds of Australia until the loss of its habitat helped drive it to extinction

A figure representing the Kayentatherium babies found with an adult specimen. They are the only known fossils of babies from an extinct mammal relative that lived during the Early Jurassic.

Weasel-Like Fossils Reveal Evolutionary Clues of the First Mammals

A protomammal known as <i>Kayentatherium</i> was discovered with 38 babies in 185-million-year-old rock

A blue whale, the largest known creature in Earth's history, dives into the St. Lawrence river in Quebec, Canada.

Today's Whales Are Huge, But Why Aren't They Huger?

Most giant cetaceans only got giant in the past 4.5 million years, suggesting they could have room to grow

The Diplodocus dinosaurs were some of the largest to walk the planet.

Tiny Skull Illuminates the Lives of Giant Dinosaurs

The skull of a juvenile <i>Diplodocus</i> is one of the youngest of these dinosaurs ever found

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