Why have birds never become as large as a T. rex?

Birds are living dinosaurs that evolved from feathered theropods

Traits associated with birds, including feathers, laying eggs, and hollow bones, were first present in dinosaurs and carried through to their descendants. Fossils of these dinosaurs have been found in a sleeping posture, resembling roosting behavior.

Dinosaurs ranged from the size of chickens to multistory buildings

The largest known dinosaur, Argentinosaurus, was about 39 meters long and outweighed a Boeing 737. Species like Parvicursor and Epidexipteryx were less than 45 centimeters long, though the actual smallest dinosaur is likely lost to history.

Air sacs and lightweight bones helped some dinosaurs grow to enormous sizes

After the Triassic extinctions, new species with birdlike anatomy evolved from smaller, early dinosaurs. This anatomy allowed for more efficient breathing and lighter skeletons, favoring the evolution of larger organisms.

Pterosaurs were dinosaur cousins that ruled the skies

Giant flying lizards or massive leathery birds? Pterosaurs were neither. What they were were the first vertebrates to fly through the skies. This National Geographic video discusses the anatomical features that made their flight possible, how big these awesome creatures could get, and which species was named after a legendary vampire.

Variations in beak shape helped birds survive the dinosaur extinction event

The asteroid that struck Earth 66 million years ago killed some avian dinosaurs. The smaller species endured by reproducing more quickly and adapting to the environment. Their different beaks allowed them to eat more varied foods for survival.

Uncovering the evolution of history's largest dinosaurs

This article details how sauropods—the dinosaurs that Little Foot would call longnecks—repeatedly evolved to attain such colossal sizes, towering over other land critters, including tyrannosaurs and mammoths. Sauropods were giant, long-necked...

Estimates say 2.5 billion total T. rexes lived on Earth

Roughly 68 million years ago, the Tyrannosaurus rex was king of the North American ecosystem. Researchers used the dinosaur's size, metabolic rate, age of sexual maturity, and other factors to determine 20,000 individuals likely were alive at any given time, more than 120,000 20-year generations. This piece breaks down how they arrived at those numbers.

T. rex didn't stomp, it walked on tiptoes like a bird

A new biomechanical study analyzing four T. rex specimens, including the famous "Sue" at Chicago's Field Museum, found the dinosaur used a "distal-first" foot strike, described as landing on its toes before its heel, similar to a modern ostrich. The technique improved stride efficiency and shock absorption, letting adults reach speeds up to 14 mph, while younger, lighter T. rexes could sprint closer to 25 mph.

T. rex hunted for prey but wasn't above scavenging rotting meat

Despite possessing a huge head full of serrated teeth the size of rail spikes, the Tyrannosaurus rex had puny, rigid arms, and scientists think it enjoyed scavenging.

Dinosaur portrayals in film mistakenly limit them to only living in tropical climates

The ancient creatures have been brought to life in cinema by combining animatronics and CGI. However, creative liberties have created misconceptions about dinosaurs for audiences, including that the Tyrannosaurus rex could not see stationary prey.

Without dinosaurs, plants could produce fleshy fruits with bigger seeds

Previously disturbed by massive herbivores, denser and darker forests shifted plant evolution, reaching the greatest diversity of seed sizes, fruit sizes, and fruit types about 50 million years ago.

How birds are becoming research assistants

Through the creation of tiny sensors easily placed on their bodies, birds have served as research assistants for various scientists. With untold numbers of birds sending back data, researchers have achieved greater insights in long obscure areas of meteorology, ecology, and more. For example, weather scientists use high-flying birds to outline the height of the planetary boundary layer, while conservationists track gulls to protect migrating whales. Learn more here.

Exploring bird skulls

Birds inspire us to fly—but what about bird skulls? This collection of various birds' preserved skulls offers a peculiar "bird's-eye" view. See the many surprising shapes of beaks and eyeholes, from mockingbirds to turkeys, in this fascinating visual collection.

The Age of Dinosaurs ended in fiery disaster

How did dinosaurs become extinct? Explore the Cretaceous extinction event and the role of the Chicxulub impact in the death of dinosaurs (except birds).

Why parrots can talk like humans

Birds are built with incredibly versatile tracheas that can mimic all kinds of sounds from their environment. For parrots, that includes human speech. This brief video explains why birds, who have such distinct anatomies from humans, are somehow able to talk like them, anyway.

Huge tyrannosaur wore a fuzzy coat

It’s not your dad’s tyrannosaur: Yutyrannus huali, a newly discovered ancestor of Tyrannosaurus rex, was covered from head to tail in downy feathers.

Large animals like giraffes and elephants have evolved unique cancer defenses

One may expect the larger an animal is, the more likely it is to develop cancer—simply because there are more cells and more chances for a dangerous mutation. However, some large animals show cancer rates almost 10 times lower than humans—a phenomenon known as Peto's Paradox.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

'Birds Aren't Real' parodies the way memes traffic conspiracy theories

Peter McIndoe claims the US government killed 12 billion birds only to replace them with drones. These statements have powered protests—and McIndoe's fictional campaign that highlights how conspiracies and their theorists are treated.

Everything to know about emus

Emus are flightless birds native to Australia, second only to ostriches in size among avians. Reaching up to six feet and weighing more than 100 pounds, the grayish-brown emu can run 30 mph, lives in small flocks, and travels widely for food and water as a nomad. Learn more about the emu's many delightful quirks in this irreverent and informative podcast.

Tigers emerged much earlier as a species than lions

Both lions and tigers are iconic big cats known for their size and power, but they remain distinct species. Beyond just looking different, they can exhibit very different behaviors. For example, tigers are significantly less social than lions, who live in social matriarchal groups. Tigers and lions are unlikely to ever interact in the wild, but humans have artificially bred them in captivity, creating a "liger."

Restaurants are ramping up chicken dishes in 'The Great Chickening'

For decades, consumption of poultry meat has been on the rise in the US. Even more recently, restaurants have been focused on using the bird, citing its reliability, versatility, and the rising cost of beef. Nonetheless, avian flu has caused prices to fluctuate.

After swallowing 23 pieces of plastic, seabirds experience a 90% death rate

Researchers found that this threshold is also met when marine mammals ingest 29 pieces and when sea turtles consume approximately 405 pieces. Almost half of the sea turtles, a third of the seabirds, and one in ten of the marine mammals studied had eaten plastic.

Technological advancements will make future wind turbines more efficient and quieter

Manufacturing larger, more powerful turbines will result in future wind farms requiring fewer of them to meet energy demands. Larger turbines will meet these demands while rotating at lower speeds, reducing risks to avian wildlife.

Ballistic experiments show that tardigrades are unlikely to be an alien species

Those fired from guns at speeds as high as 825 meters per second (1,845 mph) could be resuscitated after impact. Shock pressure from greater speeds tore apart the samples, suggesting they could not survive asteroid impacts if brought to Earth from outer space.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Explaining why animals don't cross this invisible line in Indonesia

Although the distance separating the two regions is small, East and West Indonesia have starkly different species, puzzling scientists for decades. Biogeographers use the theory of plate tectonics to explain the phenomenon, arguing the two regions...

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Animal phobias are likely the most common type of phobias, followed by an extreme fear of heights.

Scientists have struggled to pin down Ebola's natural reservoir species for decades, but the available evidence suggests that it's very likely fruit and insect-eating bats found in Africa.

American short story writer Flannery O'Connor raised 40 peacocks, which became potent symbols for her fiction's elegant violence

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Exploring the Larry Bird punch that almost changed March Madness

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

Despite being favored by 87% of Americans, Congress does not have term limits.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

The tragic Pulitzer Prize-winning image 'The Vulture and the Little Girl' (1993) generated controversy, raised concerns about ethics in photography, and eventually led to the photographer's death.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in casualties, forces mobilized, and displacement of civilians.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

Fast-casual restaurant Chili's is experiencing a resurgence, with its parent company recently reporting a nearly 32% increase in sales, thanks to passionate Gen Z fans on TikTok.

Brian Wilson wrote the Beach Boys' 'Don't Worry Baby' for the Ronettes, but the legendary girl group rejected it.