What would you do to survive? How far would you go? I don’t think any of us truly know our limits until we face a dire situation. We possess a strong animal instinct for survival, and I think most of us would do more than we believe possible to stay alive.

On a recent trip to Reno, I began thinking about the doomed Donner party, a group of pioneers who became trapped in the Sierra Nevada Mountains during the brutal winter of 1846-47.

In May 1846, the Donner and Reed families (87 men, women, and children) set out by wagon train from Independence, Missouri, headed for California. The group got a late start, leaving them little room for error on a journey which generally took four-to-six months under the best of conditions. Unfortunately, the leaders of the group made several bad decisions and luck was not on their side. The group reached the Sierra Nevada Mountains in late October 1846 and became stranded in heavy snow during one of the worst winters the region has ever seen.

By mid-December, the Donner party was nearly out of food, and a few members of the group set out on foot in search of supplies and help at Sutter’s Fort (now Sacramento). They made it to Sutter’s Fort, but due to heavy snowfall, a relief party could not reach the remainder of the group until the middle of February 1847. Only 48 of the original 87 members survived the ordeal, and not long after the party was rescued, rumors circulated across the country, suggesting the snowbound pioneers had resorted to cannibalism to survive.

The settlers finally admitted they did not murder other members of their group and then eat them, but they did consume the flesh of some of their fellow travelers who died from starvation. While this act might sound reprehensible, it’s something most of us probably would do if we were starving to death.

A more recent story of cannibalism began on October 12, 1972, when a plane carrying a Uruguay rugby team and its supporters departed Uruguay, headed for a match against an English rugby team in Santiago Chile. Bad weather forced the plane to stop overnight in Mendoza, Argentina, but the flight resumed the following afternoon when the weather began to improve. An experienced pilot flew the four-year old aircraft across the Andes, a trip he previously had done 29 times. Despite his experience, though, the pilot became disoriented in the clouds and extreme turbulence in the Andes, and he began to descend too soon, crashing into a glacier at an altitude of 11,710 feet. (3,570 m)

Of the 45 passengers and crew on the aircraft, 33 survived the crash. Many of the survivors were critically injured, though, and several succumbed to their injuries within a few days. The Chilean Air Search and Rescue Service looked for the missing aircraft for eight days. Survivors later said several rescue planes flew over them, but the fuselage of the crashed aircraft appeared invisible against the white snow, and the passengers failed to attract the attention of the searchers. After eight days, the Chilean government suspended the search, and no one believed anyone could survive a crash in the snowy Andes.

After eight days, only 27 of the original 45 passengers remained alive. The survivors fashioned a crude shelter in the fuselage of the plane and used the padding from seat cushions to stay warm. The temperature dropped to -22°F (-30°C) during the nights, and the passengers faced ailments related to high-altitude sickness and snow blindness. The survivors had little food with them, consisting of eight chocolate bars, a tin of mussels, three small jars of jam, a tin of almonds, a few dates, candies, dried plums, and several bottles of wine.

They rationed their meager food supplies for a few days, but soon the food was gone, and they found themselves on a glacier with nothing to eat. They even tried to eat the airplane seats, but the treated fabrics made them sick. On the tenth day after the crash, one of the passengers improvised a long antenna and attached it to a small transistor radio found on the plane. They picked up a news broadcast and learned the government had suspended the search for them. The crash victims knew help would not come soon, and they needed to take drastic measures if they hoped to survive.

Faced with starvation, the passengers agreed that if they died, the others could eat their flesh to survive. After making this grim pact, the desperate survivors began to eat the bodies of their dead friends.

Survivor Roberto Canessa later said, “Our common goal was to survive — but what we lacked was food. We had long since run out of the meager pickings we’d found on the plane, and there was no vegetation or animal life to be found. After just a few days, we were feeling the sensation of our own bodies consuming themselves just to remain alive. Before long, we would become too weak to recover from starvation.

“We knew the answer, but it was too terrible to contemplate.

“The bodies of our friends and team-mates, preserved outside in the snow and ice, contained vital, life-giving protein that could help us survive. But could we do it?

“For a long time, we agonized. I went out in the snow and prayed to God for guidance. Without His consent, I felt I would be violating the memory of my friends; that I would be stealing their souls.

“We wondered whether we were going mad even to contemplate such a thing. Had we turned into brute savages? Or was this the only sane thing to do? Truly, we were pushing the limits of our fear.”

At first, some of the members of the group refused to eat human flesh, but eventually, due to pangs of hunger and at the urgings of the rest of the group, they relented. Most of the survivors were deeply religious Roman Catholics, and they came to consider eating their friends and family a sort of Holy Communion.

As if their predicament wasn’t already dire, seventeen days after the crash, an avalanche roared down the glacier and landed on the survivors, killing eight individuals and burying the fuselage, trapping several survivors inside the plane. The trapped passengers painstakingly dug their way to the surface, where they encountered a fierce blizzard and had to return to the shelter of the fuselage.

Sixty days after the plane crash, two of the rugby players, Nando Parrado and Roberto Canessa, set out on a daring journey to find help. They climbed the glacier and hiked 38 miles (61 km) in search of other humans. Finally, they encountered Sergio Catalán, a mule rider who was carrying supplies through the Andes. Catalán rode for ten hours to tell authorities he had met some of the crash victims from the rugby team’s plane. After 72 days on the glacier, search and rescue helicopters air-lifted the sixteen survivors to Santiago, where they were treated for malnutrition and other ailments.

Hoping to keep their cannibalism secret, the survivors initially said they ate cheese and wild plants to survive. Soon, though, rumors suggesting the survivors had consumed their fellow passengers began to spread, and on December 26, photos taken by rescue workers of a half-eaten human leg covered the front pages of two Chilean newspapers.

The public initially condemned the survivors for eating human flesh, but when some of the passengers publicly shared the details of their harrowing ordeal, most people understood they’d had no choice; they were forced to eat their fallen comrades or die themselves.

Most of us consider cannibalism taboo, and we believe we could never resort to it, even if the alternative meant certain death. The thought of eating human flesh makes us nauseous, but could you eat your dead friend if the nutrition from his body might help you survive?

Desperation forces us to do things we thought we could never do. The Donner party and the rugby team crash survivors in the Andes tried to eat saddles and airplane seats before they finally resorted to consuming human flesh. I think most of us would do the same thing in their place. Survival, after all, is an overpowering animal instinct.