The Mystery of Pig 311 Who Was Found Alive After Bikini Atoll A-Bomb Test

In mid-1946, the United States conducted a pair of nuclear weapon tests at a remote Pacific atoll, during which numerous animals were deliberately exposed to the blasts to assess the effects of radiation.

While many of these creatures were killed immediately by the explosions, some survived—at least initially—and the mysterious story of one pig in particular has sparked fascination ever since.

This pig, known as 311, reportedly survived the first of the two atomic-bomb tests and was taken back to the U.S., where she lived for another four years.

The nuclear tests were held as part of a military program dubbed Operation Crossroads, less than a year after the U.S. dropped two atomic bombs on Hiroshima and Nagasaki on August 6 and 9, 1945.

The two tests—known as "Able" and "Baker"—went ahead on July 1 and 25 respectively at Bikini Atoll, a ring-shaped coral reef in the central Pacific, which is part of the Marshall Islands.

The aim of the tests was to investigate the effects of nuclear blasts on Navy vessels, and more than 90 ships were used as targets, including obsolete U.S. battleships and submarines, as well as surrendered German and Japanese ships. The second bomb, Baker, was detonated 90 feet underwater.

On 22 of the target ships, the U.S. military also placed thousands of animals—primarily rats, but also pigs, guinea pigs, goats and mice—to study how the bomb blasts would affect them.

"Some animals were used not only to study the effects of radiation on an individual, but also the long-term health consequences for later generations," Jennifer Knox, policy and research analyst for the Global Security Program in the Union of Concerned Scientists, told Newsweek.

"For these reasons, animals were placed at different distances from the nuclear blast or shielded with different kinds of materials, changing the dose of radiation that they received and their immediate exposure to blast effects."

How Nuclear Bombs Impact Animals

According to an official report from 1947, these animals were later removed and taken to a support ship known as the U.S.S. Burleson for examination and medical care soon after the detonation of Test Able—in which most of the creatures were used. Some animals—around 10 percent—died from the initial blast. Many others died in the days and weeks after due to the effects of radiation poisoning. Some arrived back in the United States where scientists continued to study them.

But one particularly remarkable story emerged out of the tests—that of Pig 311. According to media reports from the 1940s, this animal had been locked in an officers' toilet aboard the Japanese cruiser Sakawa during the Able test.

The blast caused Sakawa, which was located around 420 yards away from the point of detonation, to burn fiercely for 24 hours before it eventually sank on July 2.

Somehow, Pig 311 survived the blast and the sinking of its ship and was found swimming in the Bikini Atoll lagoon a day later, according to reports. Life magazine reported in a 1947 article that the piglet was the only animal survivor from Sakawa.

When the animal was found, the 50-pound, 6-month-old piglet showed signs of radiation sickness—a Time magazine article from 1949 reported Pig 311 was "irritable, and had a low blood count," but within a month, she seemed to have recovered.

Afterwards, the animal was brought back to the Naval Medical Research Institute in Bethesda, Maryland, to be studied. A year after the test, she had grown from a piglet to a 350-pound sow.

Researchers took periodic blood tests of the animal to assess what damage she had suffered from the radiation, but the pig appeared to be in relatively good condition, apart from the fact that she was sterile. Scientists had made several attempts to breed her without success, although it is unclear if this was due to the effects of the bomb.

In April 1949, Pig 311, who then weighed 600 pounds, was given to the Smithsonian's National Zoological Park in Washington, D.C., where she became a favourite of visitors to the site. Pulitzer Prize-winning journalist Walter Pincus wrote about Pig 311 in his 2021 book Blown to Hell: America's Deadly Betrayal of the Marshall Islanders.

After three years had passed since Operation Crossroads, the vast majority of the thousands of animals used in the test had died, according to Pincus. Pig 311 would soon follow, passing away on July 8, 1950—just over four years after she had been exposed to the bomb. The cause of the pig's death was not disclosed.

Was Pig 311 Ever Even on Sakawa?

Some uncertainty remains about the circumstances of the pig's seemingly heroic survival from the atomic blast. It is not clear exactly how Pig 311 made it out of the ship alive, and at least one local news article from 1946 reported that the creature had not been on Sakawa at the time of the test. An investigation had found that the pig had simply gone AWOL on the U.S.S Burleson support ship before reappearing the next day.

While the circumstances of Pig 311's story are not entirely clear, Kathryn Higley, a professor in the School of of Nuclear Science and Engineering at Oregon State University, told Newsweek that a number of factors could have had an impact on the survival of animals during Operation Crossroads.

"The detonation of a nuclear weapon results in release of high levels of radiation, high levels of heat, and shock waves. So, depending on where the animals were located, they could have been shielded from some or all of these effects," Higley said.

"When radiation impacts the body, it can damage cells. If sufficient numbers of cells are damaged, then organ function can be impaired, or even organ death can occur."

These kinds of effects can happen very quickly (with a high dose) or take weeks to months to occur (with a moderately high dose). Some of the Operation Crossroads animals survived the initial blast, but the internal tissue damage they suffered was so great that they died in the coming days to months.

"With lower doses, the cells in the body are largely able to repair the damage, but there is some potential for misrepairs to occur. Such misrepairs can set the stage, for example, to cause a cancer," Higley said.

"This type of effect is called stochastic, because the likelihood of getting cancer from exposure is based on a probability. The greater the total dose, the greater the potential, or likelihood, to have cancer—but not the potential for a 'worse case' of cancer."

Lasting Impacts of U.S. Nuclear Tests

The impacts of the test were not only felt by animals. In total, the U.S. conducted 67 nuclear tests in the Marshall Islands across the 1940s and 1950s, leaving behind radioactive contamination that can still be detected today.

"Tragically, the effects of these tests were not limited to animals," Knox said. "Native populations of Marshallese islanders were also exposed to the radiation effects and the legacy of environmental contamination left behind.

"In 2019, studies showed high levels of radioactive contaminants in soil samples and fruits taken from the Marshall Islands. The Marshall Islands are still fighting for just compensation and remediation to address the harm caused by U.S. nuclear testing."

Survivors are still suffering from the humanitarian consequences of these tests and have experienced a significantly higher rate of cancer, stillbirths, miscarriages, congenital birth defects and reproductive problems, among other long-term health and environmental consequences.

Alicia Sanders-Zakre, a policy and research coordinator with the International Campaign to Abolish Nuclear Weapons, told Newsweek: "The increasing risk that nuclear weapons could be used again today makes it even more urgent that we support those who are already living with the effects of the attacks in Japan and of the tests carried out in many other countries since 1945, and that we make the world aware of the devastating impact they have.

"The Treaty on the Prohibition of Nuclear Weapons [signed in September 2017, effective from January 2021] presents the only realistic pathway to eliminating the risk of nuclear weapons use by eliminating the weapons themselves. All countries must join this treaty without delay."