Pigs are of particular interest for xenotransplantation because they are close to human size, are easily raised in captivity, and have large litters.

Pig-to-human transplant work has raised concerns about donor pigs' living conditions.

Explore different pig-to-human xenotransplantation possibilities, including using pig pancreatic cells for treating diabetes.

Xenotransplants are an experimental last resort for the terminally ill when they cannot or will not receive a human organ.

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

Chinese scientists transplanted a pig lung into a human being in 2025—but it had to be removed.

See how pig heart valves have been placed in humans since 1965.

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.

Read why one man agreed to get a pig kidney in 2025 to replace his own failing organ

The 68-year-old New Hampshire man told USA Today that a motivator for the experimental surgery was his belief that he was going to die anyway, and other people suffering from kidney disease could gain valuable insights. Yet the surgery bought him time—he lived 271 days with a pig organ and later received a human kidney transplant. Clinical trials began in 2026 to test the pig xenotransplants in more people.

After the first gene-edited pig heart transplant patient died, a latent pig virus was discovered inside his xenotransplant.

Alpha-gal allergy is a problem for red meat lovers, and that same alpha-gal sugar is an issue for xenotransplants, too—since it's present in pigs, human bodies reject pig-to-human transplants as foreign once they detect the substance.

A first-of-its-kind clinical trial taps livers from gene-edited pigs to clean blood

The experimental dialysis-like treatment from United Therapeutics, eGenesis, and OrganOx, is designed to help people with liver failure. The therapy, which involves attaching the modified pig liver externally, filters a patient’s blood so their own livers can temporarily rest and perhaps heal.

US federal researchers are blocked from putting certain human cells in animals

In 2015, US policymakers put a halt to any government-funded work that would insert human stem cells into animals. The reasoning was that human cells might spread through the animal's body and perhaps to its brain, blurring the line between humans and nonhumans. The ban remains in place today even as gene-edited pig parts are being placed in humans.

The global xenotransplantation market may already be valued at more than $13B.

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.

One man lived with a gene-edited pig kidney for 271 days, setting a record, before he received a human kidney.

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.

Early peptide research focused on isolating the substances from animal tissue

In the first half of the 20th century, peptides including insulin and adrenocorticotropic hormone were isolated from animals to provide life-saving medicines. ACTH was isolated from the pituitary glands of cows and pigs and insulin was isolated from the pancreas of dogs and cows.

Meet Icarus the Second, the first English pig to fly

"When pigs fly" is an ironic phrase meant to express disbelief or impossibility, though it isn't as true today as it may once have been. This article details how a piglet dubbed "Icarus the Second" took flight in November 1909. Stashed in a basket...

Pig brain cellular activity was restarted hours after death in study published in 2019

Yale University scientists restored basic cellular activity and circulatory function in pig brains about four hours after death with a synthetic cocktail of preservatives and nutrients. This work— which didn't restart electricity activity in the brain or consciousness—could help advance future human stroke and brain injury treatments.

Chimpanzees are dying from human colds

For some great apes, the threat of human-borne diseases outweighs poaching or habitat loss. This article details the danger of reverse zoonoses, which refers to diseases that spread from humans to animals.

Researches have found that various monkeys have pet-like relationships with other species.

Scientists William Russell and Rex Burch proposed in 1959 that when it comes to animal testing, there should be 'three Rs'—replace animals wherever possible; reduce their numbers; refine how they're treated.

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

In 1984, a dying infant lived for three weeks with a baboon heart inside her chest.

Using artificial wombs to improve preterm infant health outcomes

Researchers at a hospital in the US have successfully used artificial wombs to care for preterm lambs and are now looking at the possibility of human trials. This nine-minute video includes interviews with the researchers and explains the reasoning...

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.

Scientists have demonstrated IVF to help critically endangered rhinos

Scientists have used the technique to create embryos from eggs harvested from captive southern white rhinos and implanted into a southern white rhino. They hope to use this proof of concept to eventually use IVF to revive the population of northern white rhinos, which are extinct in the wild and have no living males left, using a precious reserve of frozen embryos and a surrogate southern white rhino mother.

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

Zoonotic diseases: Pathogens that jump from animals to humans

Such diseases may be caused by a variety of pathogens—viruses, bacteria, fungi, or parasites—and can originate in creatures ranging from ticks and mosquitoes to pigs and bats. Because they develop in animals and are often new to human immune systems, zoonotic diseases have severe consequences for public health.

Scientists using gene therapy recently managed to regenerate retinal cells in the lab—a breakthrough for mammals that could potentially lead to future treatments for human retinal diseases.

Large animals like giraffes and elephants have evolved unique cancer defenses.

Animal-to-human pathogens constitute 75% of emerging infectious diseases

Zoonotic diseases encompass more than 200 diseases transmitted from animals to humans, wherein humans are usually accidental hosts. Ranging from rabies to HIV to monkeypox, this overview lists some of the most common viral threats.

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.

It took scientists 277 attempts to successfully clone Dolly from an adult sheep mammalian cell, underscoring the immense undertaking and challenges—some of which still persist today.

Six pigeons were trained to detect cancer from looking at CT scans—now that work is the basis for training new AI medical tools.

Humans are more genetically similar to cats than to dogs

While humans are not closely related to either cats or dogs from an evolutionary standpoint, scientists find that human and cat chromosomes are organized more similarly to each other than human and dog chromosomes, making cats a better model for studying human diseases.

As of 2025, perfect synthetic replication of natural organs remains elusive

Advancements such as 3D printing muscles, performing vaginal reconstruction with colon tissue, and growing organs in a lab have shown promise, but artificial options and transplanting substitutions continue to exhibit functional and performance limitations compared to their natural equivalents.

Scientific advances are unlocking a wide range of alternatives to IVF

From refined artificial insemination and microsurgical sperm extraction to experimental uterine transplants, scientific innovation is rapidly advancing potential fertilization technologies. But they come along with costly trials, some ethical dilemmas, regulatory issues, and more.

Before modern sanitation, New York City let pigs roam the streets to eat its garbage

In the early 1820s, an estimated 20,000 hogs roamed Manhattan's streets, feeding on trash that the city lacked a system to collect. Pigs were eventually banned at the urging of wealthy residents, who feared they would deter tourists and drive down property values.

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.

Biotech is trying to boost drug production efficiency—using chicken eggs

A company called Neion Bio is genetically engineering birds in a bid to produce medical compounds, a herculean task that scientists have struggled with for decades. The US FDA has approved only one chicken-derived drug in the past—an expensive treatment for a rare liver disorder. (Some users may encounter a paywall.)

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.

No one is tracking the total number of animals used for research across US labs, though partial data without any rodents puts the 2024 count above 775,000 animals, including some 40,000 dogs and 100,000 primates.

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

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.)

In vitro gametogenesis: using induced stem cells to fertilize eggs

Using stem cells from skin and mouth cells could save hopeful parents time and money and spare egg donors from significant amounts of discomfort throughout the process. There are potential consequences, not just for infertility treatment, but for the ability to create customized cells of any type.

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.

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.