Evolution

For rabbits and hares, females typically weigh more than males, according to a new study.

For Most Mammal Species, Males Actually Aren't Larger Than Females, Study Finds

New research upends a long-held theory that male mammals tend to be bigger than their female counterparts

An illustration of the fossil skeleton of the new bird species Imparavis attenboroughi and a reconstruction of what the animal would have looked like in flight.

'Strange' New Prehistoric Bird Discovered in China and Named for David Attenborough

The proto-bird lived some 120 million years ago and did not have teeth—a trait more similar to birds of today than to birds of its time—sharpening scientists' understanding of avian evolution

P. karlraubenheimeri lived during the Miocene Epoch roughly 8.8 million years ago.

Fossil Hunter Discovers Gigantic Crab in New Zealand—a New, Extinct Species

The massive creature is 8.8 million years old, and its modern descendants in Australia can grow to be the weight of a human toddler

A mutation in a gene called TBXT may be behind the loss of great apes' tails, according to a new study.

Why Don’t Humans Have Tails? An Old Genetic Mutation Could Explain Why Monkeys, but Not Apes, Have the Extra Appendage

Scientists have pinpointed a genetic change that might have led the ancestors of humans to lose their tails

The cat-eyed snake slithers in the Peruvian Amazon.

A Serpentine 'Explosion' 125 Million Years Ago Primed Snakes for Rapid, Diverse Evolution

Researchers say an evolutionary "singularity" led to several small, quick changes in snake species, from legless bodies and flexible skulls to chemical-sensing abilities

An adult humpback whale and calf. In the new study, the researchers blew air into the larynxes of three deceased whales, including a humpback, to learn how the the organ makes sound.

Scientists Discover How Some Whales Can Sing While Holding Their Breath Underwater

Baleen whales have evolved unique voice boxes essential for song, a new study finds—but these low-frequency vocalizations must compete with the noise of humans' ships

Roger Federer hits a forehand shot at Wimbledon. The tennis great has called his racket an extension of his arm.

How Did Humans Evolve to Use Everyday Tools?

An anthropologist explains why we experience many objects, from tennis rackets to cars, as extensions of our bodies

Short attention spans could be helpful for foragers, since switching quickly between food sources when exploring could lead to a higher yield, researchers suggest.

ADHD Traits Might Have Helped Hunter-Gatherers Collect More Food While Foraging, Study Suggests

Participants who self-reported ADHD behaviors were better at an online berry-picking game than those who did not report such traits

In a study of great apes' playful antics, chimpanzees seemed to enjoy slapping adults, especially those that were dozing off.

Great Apes Love to Tease, Poke and Pester, Suggesting the Urge to Annoy Is Millions of Years Old

The desire to get a rise out of others is a 13-million-year-old trait humans and great apes share with a common ancestor, new research suggests

Delias sambawana, a butterfly that hails from Indonesia, at the Florida Museum of Natural History.

Where Did Butterflies Come From? This Scientist Is On the Case

Akito Kawahara has spent his life devoted to lepidoptera. Now he’s correcting the record on where they first evolved

An etching of Darwin's study, commissioned a week after he died.

See What Charles Darwin Kept in His 'Insanely Eclectic' Personal Library, Revealed for the First Time

On the English naturalist's 215th birthday, more than 9,000 titles from his expansive collection are now accessible online

The newly discovered tree would have supported a wide crown of leaves over a narrow trunk, scientists say.

Rare Fossil Shows Trees Looked Very Different 350 Million Years Ago

The newly discovered specimen looks like something from the imagination of Dr. Seuss, and it sheds light on a little-understood era of prehistory

For species that reproduce sexually, every offspring is a gamble. Each has slightly different genes, giving it the potential to be carrying helpful, adaptive traits.

Can Animals Evolve Fast Enough to Keep Up With Climate Change?

Some may be able to, while others may not

Dogs are one of the few animals that use their tails primarily for communication.

Why Do Dogs Wag Their Tails? Scientists Examine the Endearing Behavior

Dogs communicate through tail-wagging, and humans may have selected for the trait during domestication

The 160-year-old pelt of the woolly dog Mutton in the Smithsonian’s collection

What Happened to the Extinct Woolly Dog?

Researchers studying the 160-year-old fur of a dog named Mutton in the Smithsonian collections found that the Indigenous breed existed for at least 5,000 years before European colonizers eradicated it

An artist's impression of Gigantopithecus blacki near a forest in southern China.

What Caused the Mysterious Extinction of 'Giganto,' the World's Largest Ape?

The massive primates were unable to shift their diet to keep pace with a changing climate, according to a new study, forcing them to eat less nutritious bark and twigs

Cyanobacteria, or blue-green algae, on the surface of a lake. Bacteria were the first organisms to photosynthesize, creating the oxygen essential for the evolution of life on Earth.

Scientists Uncover the Earliest Fossil Evidence of Photosynthesis

Ancient cyanobacteria contained structures for producing oxygen around 1.75 billion years ago, according to a new study

An artist's depiction of a person carving a pendant from bones of a giant sloth roughly 25,000 to 27,000 years ago. Research this year suggested humans and the sloths lived in Brazil at the same time, strengthening evidence that our ancestors populated the Americas earlier than thought.

Thirteen Discoveries Made About Human Evolution in 2023

Smithsonian paleoanthropologists reveal some of the year’s most fascinating findings about human origins

Electric eels can discharge up to 860 volts of electricity.

Eels Can Genetically Modify Nearby Fish With Their Electrical Pulses

In laboratory experiments, gene transfer occurred in 5 percent of zebrafish larvae that were near eels when they discharged electricity

Female mosquitoes need to drink blood in order to produce their eggs.

Male Mosquitoes May Have Once Sucked Blood, Amber Fossils Suggest

Today, only female mosquitoes feed on the blood of animals, while males are satisfied with plant juices

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