The body of Dolly the sheep, the world's first cloned mammal, is preserved and kept on display at the National Museum of Scotland.

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.

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

World's first cloned yak

China has successfully cloned a yak for the first time, using somatic cell cloning and genome selection to enhance traits like strength, health, and disease resistance.

Inside the world's largest two-headed calf collection

The Two-Headed Calf MOOseum in San Francisco contains 50 taxidermied cow heads, all of which are paired with another one. They are the result of rare genetic mutations called polycephaly, that is, two-headedness. The museum is run by punk musician Henry Rosenthal, who first became captivated by the rare phenomenon in his 20s. Learn more about the exhibit here.

When was the first blood transfusion?

In the 1600s, an English doctor transferred the blood from one dog to another via quills. The procedure ended when one of the dogs died. This article details the early days of blood transfusions, which turned toward humans shortly after the 1666 dog experiment and involved putting the blood of a sheep into a human recipient (who reportedly survived the encounter).

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

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

The Amazon molly is an all-female organism that has been cloning itself for 100,000 years without accumulating harmful mutations.

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

The first successful IVF pregnancy was in the United Kingdom in 1978

Gynecologist Patrick Steptoe and his collaborator Robert Edwards, a biologist, attempted to fertilize a human egg cell in a petri dish 101 times before finally succeeding. This resulted in the birth of Louise Brown—at the time referred to as a "test tube" baby—in 1978, who was born into the spotlight.

Herd behavior has been seen in 193-million-year-old dinosaur fossils

Scientists excavated eggs, juveniles, and adult remains in Patagonia, all arranged by age group. The organization into structured groups may have contributed to evolutionary success by consolidating eggs in one location to make defending them easier.

Meet Pauline, the White House cow who made national news when she briefly went missing on her way to a dairy show.

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

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.

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

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

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.

Sheep once grazed on the National Mall and White House grounds

In the late 1910s, sheep grazed near the Lincoln Memorial and on the White House lawn. Under Woodrow Wilson, their wool was auctioned for charity, briefly making the grazing animals the subject of a federal cost-saving experiment.

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...

Watch wild elephants 'mourn' their dead

Wild elephants in Samburu National Reserve in northern Kenya visited their dead matriarch's body weeks after her death and displayed behaviors that researchers are hesitant to call "mourning" though they do believe the animals are displaying a specific reaction in response to the death. The video shows elephants using their trunks to touch and explore the carcass while standing in place for extended periods, which is uncommon for the animals.

Whose bodies are held inside the American Museum of Natural History?

The American Museum of Natural History holds the remains of at least 12,000 people collected via purchase, donation, or expedition. This article by a professor of art crime details their attempt to identify the individuals whose remains the museum held. Amid questioning, AMNH announced it would change its human remains policy. At the time of the article's publication in October 2023, AMNH had few human remains on public display.

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

The first dinosaur bone ever discovered in Antarctica—a tail bone from a titanosaur—sat in storage for over 40 years before scientists realized what it was.

The Dog Aging Project uses information from over 50,000 dogs to explore longevity

The study gathers health, lifestyle, and genetic data to understand what helps dogs live longer, healthier lives. Findings could also provide human health insights due to our shared surroundings and biology.

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

A Tennessee children's hospital changed its name to Dolly Parton Children's Hospital.

Henrietta Lacks' tumor cells became the first recognized 'immortal' cell line about 75 years ago, but researchers are still investigating the specific mechanisms that enabled the cells to continuously grow and divide in the laboratory.

An 18th-century woman tricked doctors into believing she gave birth to rabbits.

Before the first human spaceflight in 1961, scientists sent fruit flies, monkeys, and dogs into space.

See the first dog ever treated with insulin—a peptide

Frederick Banting and his graduate student Charles Best were the first to isolate the peptide insulin from dogs. They induced diabetes in the animals and then treated them with this peptide.

Dinosaurs suffered from cancer, arthritis, and infections seen in modern animals

Using CT scans and advanced pathology techniques, paleopathologists have identified respiratory illnesses, malignant osteosarcoma, and other diseases in dinosaurs. The research has helped show how many of these ailments are not exclusively modern phenomena.

60 years after seeing Henrietta Lacks as a patient, her doctor still remembered the unique cervical tumor that gave rise to the 'immortal' cell line now commonly used in biomedical research—it was purple, shiny, and soft—an appearance he said is very different from a typical tumor.

‘Hope for Healing’: The first-ever use of an in utero stem cell treatment

In 2023, researchers at UC Davis performed the first-ever fetal stem cell transplant, attempting to cure a case of spinal bifida prior to childbirth using stem cells derived from the placenta. The trial, and others including an effort to treat muscular dystrophy, highlight the potential power of stem cell therapy.

Dolly Parton produced the original 'Buffy the Vampire Slayer' movie.

Without the option of modern blood transfusions, some doctors in the mid-1800s tried to help save cholera patients by injecting them with cow's milk, hoping it would boost their nutrition and hydration.

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.

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.

Read a 1984 interview with Dolly Parton, conducted by artist Andy Warhol.

A scientist successfully treated her own breast cancer by injecting the tumor with lab-grown viruses.

Mammals gradually expanded in size and diversity after the dinosaur extinction

After an asteroid impact caused a mass extinction event 66 million years ago, small mammals were among the few surviving species. With fewer predators, mammals steadily grew larger as new habitats emerged.

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.

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

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.

You can sign up to donate your body to science

It's a separate process to donate your body for medical research; you usually must contact a whole-body donation program directly. Bodies can be donated for medical research, for forensic analysis research, or for medical students to work with as they learn anatomy and surgery, among other purposes. Learn more about numerous accredited organizations that provide human bodies, organs, and tissues to medical researchers and students.

See photos of rare spotless giraffe born at zoo

A spotless giraffe was born at a zoo in Tennessee in the summer of 2023, with experts claiming the specimen is the only solid-colored animal of the species with genes for "reticulation," or the normal patchwork look. The phenomenon is so rare many...

Four frozen embryos in the US were created via 3-parent IVF technique

Columbia University researchers created four embryos using mitochondrial replacement therapy for four female patients who didn't want to pass on mitochondrial diseases to their children. Yet US law restricts the researchers from implanting the embryos so they remain frozen. (Some users may encounter a paywall.)

The oldest DNA recovered so far is 2 million years old

The oldest DNA recovered so far is about 2 million years old and has given scientists an unadulterated peek into ancient history. This nine-minute video explores the findings and implications of the DNA, which was pulled from frozen soil in...

Georges Cuvier used his knowledge of anatomy to prove extinction had occurred

Extinction had been viewed as impossible because a divine plan for the world would not rationally involve the loss of any of God’s creations. However, mammoth and mastodon bones differed from elephants’, and it seemed impossible that such creatures could be hiding elsewhere on Earth.

Dolphins have doulas too?

For the first time in over a decade, a dolphin gave birth at Brookfield Zoo, and she didn’t do it alone. Right beside her was another dolphin, acting as a doula. Why do dolphins support each other this way? The answer reveals something incredible about how animals care for one another.

Cadaver dogs are helping archaeologists uncover decaying history

Archaeologists are increasingly relying on dogs to help find decaying bodies at burial sites, some of them up to thousands of years old. This is helping archaeologists to detect past remains without ever touching a shovel, which means there's less...