At one point in the 20th century, more than a million Americans had pet monkeys

Baby monkeys chose a soft, warm doll over a wire one with food

Harry Harlow performed controversial experiments with newborn monkeys, separating them from their mothers and letting them bond with stand-in mother figures made from either wire or figures covered in cloth—both with monkey-like faces. The work investigated touch, bonding, and attachment, and found that monkeys overwhelmingly preferred the cloth dolls over the wire ones in various stressful situations.

Yes, many animals get malaria—not just humans

Birds, rodents, monkeys, lizards, bats, apes, and livestock are among the species that can become infected with malaria. Infected animals' symptoms often resemble those of humans, including fever, lethargy, loss of appetite and difficulty breathing. Birds will also have ruffled feathers and drooped heads.

Increasing contact between humans and wild animals is driving zoonotic threats

Zoonotic diseases, which spread from animals to humans, present one of the most significant emerging threats worldwide. Scientists have identified around 200 viruses capable of infecting humans, and unfortunately, the number of such diseases are on the rise—at least 60% of all emerging infectious diseases are zoonotic in origin.

Can animals understand fairness?

Academics have long wondered if fairness is solely a concern of humans. In the largest meta-analysis to date, UC Berkeley researchers tested whether monkeys felt jealousy after receiving unequal rewards. The patterns showed low evidence for inequity aversion and instead frustration due to their expectations not being met by humans. These findings suggest that pursuing fairness and equality is uniquely human.

Why humans evolved single-child pregnancies

While birthing twins has been a rare occurrence for humans, research suggests that twins were actually the norm much further back in primate evolution. It’s proposed that single-childbearing turned out to be critical for the evolution of larger babies with larger heads. Discover more about the shift that gives insight into primate evolution.

Wild chimpanzees have been spotted with leprosy lesions

In research published in 2021, scientists reported discovering cases of leprosy in wild chimpanzees from Guinea-Bissau and the Ivory Coast—marking the first time the disease has been found in any nonhuman species in Africa. They confirmed that leprosy was the cause of the deformities by testing the animals' poop for the presence of the disease-causing bacteria.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Why bananas are in trouble

The average American eats over 25 pounds of bananas every year, but we won't for long if a deadly soil fungus continues to spread. Learn what scientists are doing to save the popular fruit.

Pulitzer Prize-winning historian Edward Larson explores the Scopes Monkey Trial

The 1925 Scopes Monkey Trial was referred to as the "Trial of the Century" at the time, and has been since viewed as one of the origins of modern culture wars. A symbolic clash between science and religion during a period of rapid cultural change, the case became a flashpoint of differing ideologies.

Animals get SAD—especially those in zoos, like pandas

Giant pandas in locations outside their evolved latitudinal range (from southeast Asia to northern regions around Beijing) exhibit more sluggish behavior, even when they were born there. Researchers have observed that similar sensitivities to "photoperiods" (or time with light) impacts many animals, including birds, insects, and our pets. (Nautilus imposes a metered paywall.)

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Cats began cozying up to humans around 10,000 years ago

The feline family is a hugely diverse group of lions, panthers, and kitties that have spread all over the world. The ancestors of the cats we love today helped solve rodent problems when humans first invented agriculture. They've been worshipped, loved, and scorned by humans since.

Humans may have evolved to need less sleep

Humans sleep less than most primates—but more efficiently. Chimps sleep 9.5 hours with 5% in REM, while humans get seven hours with 25% in REM. Some predict we may one day need just five hours, but for now, our sleep patterns balance rest and function, shaped by evolution and environmental stability.

Pigs are preferred for xenografts because of their size and low disease risk

Pigs are of particular interest for xenotransplants because the animals are close to human size, are easily raised in captivity, and have large litters. They’re already routined killed for food and they’re less genetically related to humans than nonhuman primates, which reduces disease transmission risks and some researchers’ ethical concerns.

See a ranking of the most memorable presidential pets in history

This list highlights famous White House animals—from Abraham Lincoln's goats, Nanny and Nanko, to Joe Biden's German shepherds, Champ and Major—showing how pets have long been part of presidential life. (Some readers may experience a paywall.)

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Brain-computer interfaces create a direct link between the brain and external devices

The technology enables users to control prosthetics, computers, or even games using only their thoughts. In 2021, a monkey played table tennis using only its brain, thanks to a Neuralink device, marking a major milestone before human trials began in 2024.

Salvador Dalí had pet anteaters he (supposedly) took on walks

Known for his adept and weird public relations stunts, Dalí kept exotic pets, such as an ocelot named Babou, as well as anteaters. The insectivorous mammal accompanied him on walks (though it may have just been for a photo op) and on talk show appearances.

There's a booming community of jumping spider pet owners

Jumping spiders have become hugely popular pets, especially amongst women, and they can cost up to $100. Some get them in an attempt to overcome their fear of spiders, while others just find them adorable. The practice has led many people to appreciate the complexity of the animal that some would consider a pest.

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

Inside the pigeon race with $50K at stake

More than 1,000 pigeons are released each year at the American Racing Pigeon Union convention as owners wait to see which of the birds arrives home first. This essay unwraps the niche activity's paradoxical love for the birds despite its at times utilitarian treatment of them.

The human cost of creating medieval monsters

The concept and creation of monsters have been used since time immemorial to communicate social norms and the consequences of breaking them. Some so-called monsters were judged as such solely due to having features that would be considered birth defects in modern times. This in-depth article explores the human cost of creating medieval monsters, many of whom were defined by a physical appearance that deviates from the expected.

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.

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

This podcast delves into the history of Periplaneta americana and explores why the bugs elicit such fear, disgust, and, at times, shame. The bug likely climbed aboard the slave ships because they had both unprotected food sources and places to hide during their journey.

Two marsupials thought to be extinct discovered in New Guinea

The pygmy long-fingered possum and the newly described ring-tailed glider were discovered in 2026 after scientists believed the species had been extinct for 6,000 years. The pygmy long-fingered possum is partially defined by its unusual trait of one finger on each hand that is twice as long as the others.

Washington systematically introduced and popularized mule breeding in the United States

Known as "the father of the American Mule," Washington imported a prized Spanish donkey and bred it with a female horse at Mount Vernon. He promoted mules as stronger, more efficient farm animals, helping spread their use across the South and transforming American agriculture.

Fruit fly experiments show personality emerges, in part, from genetic factors

A 2025 study revealed that fruit flies exhibit unique behavioral preferences, akin to personalities, which could be artificially selected for when breeding to modify behavioral variability. This variability can be adaptive in unpredictable environments.

Why Americans keep buying McMansions

Some argue that McMansions—large, relatively newly built, amenity-filled, cookie-cutter homes—are ugly. Others say they're just not a good investment. And yet Americans continue buying them. This video explores why McMansions are still popular despite these criticisms, and how these homes got their start in the first place. Watch the video here.

Learn how monoclonal antibodies, which mimic the body's antibodies, can fight diseases like Ebola.

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.

See how to make a baby with 3 parents, a process called mitochondrial replacement therapy

This primer video dives into the science of mitochondrial disease risks, how this controversial mitochondrial replacement technique can work, and why proponents say this reproductive advance—already legalized in the UK and Australia—is needed in the United States.

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

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

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.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

In 2018, 26-year-old missionary John Allen Chau was killed by tribesmen after attempting to reach and evangelize on India's isolated North Sentinel Island

The United States has had a tumultuous relationship with Cuba since its 1959 revolution, highlighted by a nuclear crisis and a decades-long trade embargo.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

The Beatles' US label rejected the band's first two singles, 'Please Please Me' and 'From Me to You,' with one executive calling the band 'dead in the water.'

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

20,000 letters to the advice columnist 'Dear Abby' provide insight into prevailing sex, religion, and LGBTQ fears, anxieties, and concerns from the 1950s onward.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight