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

Pig-to-human transplants have raised concerns about pig living conditions

Pigs are the current first choice for xenotransplantation procedures, yet such work gives some researchers and animal welfare advocates pause. Concerns include that pigs would have a poor quality of life since the animals must live in a strictly-controlled, hyper-clean environment to avoid risky pathogens.

See different pig-to-human xenotransplantation possibilities

Xenotransplantation can include the insertion of any organ, tissue, cells or fluids from any nonhuman animal into a human. This US Food and Drug Administration graphic about pig-to-human applications shows different possibilities, including the exploration of using pig pancreatic cells for treating diabetes.

Xenotransplants are an experimental last resort for the terminally ill

David Bennett Sr., the world’s first genetically modified pig heart transplant recipient, explained his reasoning to his University of Maryland Medical Center care team in 2022 regarding why he accepted a pig organ: He was dying and ineligible for a human heart transplant so this was a last-ditch effort, he said. He died two months after receiving the heart.

Chinese scientists transplanted a pig lung into a human being—but it had to be removed

In August 2025, Chinese scientists transplanted a pig lung into a brain-dead person, a common research step for this type of experimental work. Researchers used CRISPR technology to alter six proteins in the pig genes to make the organ seem less foreign to the human immune system. Within a day there were indications the organ wasn’t functioning well and that the person’s body was rejecting it. Scientists ended the experiment after nine days.

Cross-species transplantation has been attempted in medicine for more than 300 years

Early reported xenotransplantation attempts included 17th century efforts in France to transfuse blood from animals into humans. The poor results prompted France to issue a xenotransplantation ban. In the 19th century, researchers tried animal-to-human skin grafts from species including sheep, rabbits, dogs, cats, rats, chickens, and pigeons.

Pig heart valves have been placed in humans since 1965

The first successful use of a pig heart valve in a human was reported in 1965. This 2015 video details why humans have been able to use pig animal valves for so long with good results and how that differs from what's needed for whole organ transplants.

Scientists may have discovered why gene-edited pig kidneys are rejected in humans

In November 2025, researchers studying how a brain-dead donor’s body responded to the transplantation of a genetically engineered pig kidney, published that they’ve identified immune system reactions that may explain why these pig organs get rejected. What’s more, they were able to reverse the rejections with an already available drug combination and the kidney functioned well. They also pinpointed a way to detect a potential rejection up to five days sooner.

Pig organ transplants are apparently kosher—you just can’t eat them

Science writer Mary Roach speaks with journalist Terry Gross about her latest book, “Replaceable You: Adventures in Human Anatomy” and discusses topics including why pig organs have become of such interest and what religious leaders have told her about pig organs and compliance with Jewish dietary law.

Model organisms like yeast, mice, and flies help scientists decode the human body

Some species are used to quickly study the effects of human diseases and treatments because they are short-lived and have similar systems to those found in humans. Bacteria, like E. coli, have been used as human proxies given their rapid growth and ease of genetic manipulability.

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.

Alpha-gal allergy is a problem for red meat lovers, and that same sugar is an issue for xenotransplants, too

In recent years, researchers have discovered ticks can induce spontaneous meat allergies in people they bite, a particularly problematic condition for previous meat lovers. This 18-minute podcast from RadioLab breaks down the cause.

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

In medieval France, pigs were once put on trial

Pigs are omnivorous animals. There are hundreds of records of pigs killing and eating children in medieval Europe. In France, these tragedies often resulted in trials and then hangings. Some pigs were held in jail for years before being executed.

Watch a pro butcher turn half a pig into eight common meals

The variety of food derived from a pig is enormous—from the common hot dog to delicate capicola. Watch butcher John Ratliff transform this meat into the basis of some of the most well-known meals.

Animal wines: Wine bottles with pigs on the label had the lowest median prices at $23.22

If you’ve ever spent too much time staring at a shelf in a wine store, you might have noticed something similar: animals, specifically, cats, pigs, or birds on the labels. So, what do these wines have in common? This interactive tool attempts to figure out what wines that include the same animal have in common.

John Steinbeck often drew a pig with wings next to his signature, a character he affectionately called 'Pigasus.'

Using mosquitoes to vaccinate bats could curb the spread of deadly diseases

Researchers in China tested a transmissible rabies vaccine in the lab by feeding mosquitoes blood containing the vaccine and observing what happened to bats when they were either bitten by the mosquitoes or fed on them. The bats developed antibodies against rabies and survived subsequent rabies infection. (Some users may encounter a paywall.)

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

Selecting an embryo based on polygenic score is illegal in the UK, Israel, and swaths of Europe

Though their use for embryo selection is illegal in many locations, private clinics in the US may offer polygenic scores to inform embryo selection. The US Food and Drug Administration has not banned their use—instead the tests are regulated like supplements, meaning they are not regulated before they come to market but consumers can file complaints and then the agency may take action.

Prosthetics and orthotics have been 3D printed to improve the lives of animals

Shells for hermit crabs, wheelchairs for guinea pigs and dogs, and horseshoes for improved running performance have been created using 3D printers. Other artificial body parts made using this technology include a jaw for a loggerhead turtle, a beak for a toucan, and a tail for an American alligator.

Humans are the only known reservoir of poliovirus

The virus has not been found in any other species, which makes humans the only known reservoir for polio. In laboratory settings, nonhuman primates have also been infected with the virus, but there's no evidence that they contract the virus in nature.

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

This choice to domesticate monkeys proved to be trickier than expected, and thus isn't a very appealing option for humans. Monkeys breed more slowly than other animals, while also being susceptible to diseases and challenging to contain.

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

Fungi have been used to restore island habitats in the central Pacific

After removing 1.5 million invasive coconut palm trees and eradicating the black rats that fed on them, as well as seabirds and crabs, conservationists working with the US Fish and Wildlife Service identified areas where fungi could be transplanted to provide nutrients to native trees. These trees serve as nesting sites for seabirds whose guano nourishes coral reefs.

Humanity's reduced body hair slows down wound healing

Cuts to human skin take twice as long to heal compared to chimps and other mammals. Scientists argue this is due to the reduced number of hair follicles on human bodies. Hair follicles contain stem cells which help repair skin cells faster, so as humanity shed its hair over time, so to speak, it also slowed its wound healing.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Harvard drowned rats for this?

Harvard's 1950s rat study was ethically questionable, but scientifically profound. One rescue attempt made rats swim 40x longer. The finding: hope isn't poetic, it's biological.

Explore a gallery of tardigrades

Although sometimes called moss piglets, tardigrades are most often white or clear with some dark pigments. Tardigrades only move by crawling, not swimming, and depictions of organisms with caved-in heads or other coloration result from sample preparation for microscopes.

What do people do once GLP-1 medications succeed at weight loss?

The drugs have been adopted by 1 in 8 Americans, with many achieving their prescribed weight loss. They now face the question of how to keep the weight off, the key issue with any weight loss program that researchers have known about for decades. Each case is unique. Some folks continue to use GLP-1s like Ozempic in minuscule doses, while others taper them off over time.

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.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

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

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.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Famed poet TS Eliot rejected the manuscript for George Orwell's political fable 'Animal Farm,' writing that its criticism of authoritarianism was not 'the right point of view.'

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.

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.

Cultural norms about how to handle the bodies of loved ones in communities in West Africa have hampered Ebola responses.

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.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

An initial public offering or 'IPO' is the process of a private company becoming public by putting shares of the company on the stock market for purchase.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

The Brothers Grimm were lawyers before they were storytellers, and became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

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

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.