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Just occasionally, natural disasters provide scientists with ‘experiments
of nature’ which give them information not available by normal means. For
instance, the eruption of Mount St Helen in 1980 and the great Yellowstone
Park fire of 1988 were gifts to ecologists interested in succession in newly
establishing ecosystems. Donald Grayson, an anthropologist at the University
of Washington, Seattle, has been studying an experiment of nature of another
kind: it involved disease, starvation, murder and cannibalism among an ill-fated
band of 19th-century pioneers of the American West.

American folklore is rich with stories of the hardships encountered
by those who explored and settled in the United States. These almost mythic
tales speak of the better life that was to be found on the ever-beckoning
frontier, of the chance of riches awaiting those with the courage and determination
to seize the opportunity. Yet some of the episodes that have become near-legends
are those of utter failure, rather than success. Few disasters have captured
the public imagination like the dismal fate of the Donner party in 1847.
Eighty-seven pioneers, led by George and Jacob Donner, attempted to cross
the arid Great Basin of Utah and Nevada en route to Sacramento, California,
using an untested trail known as the Hastings Cutoff.

In the end, barely half of the original party survived. The victims
succumbed to various manifestations – natural and unnatural – of hunger
and cold. The tragedy that befell them provided a perfect scientific test
for Grayson: ‘a case study of demographically mediated natural selection
in action’, as he said in a recent issue of the Journal of Anthropological
Research. With an eye to history, Grayson has made a study of the records
of the fate of the Donner party, describing it as ‘a human group that was
almost fully exposed to the vagaries of an exceedingly harsh and demanding
environment’. Under these circumstances, social and demographic factors
such as gender and age would be expected to affect individuals’ chances
of surviving. Indeed, demographers have made survival predictions based
on such factors. This was Grayson’s aim: to test how well those predictions
stood up in real life.

Dissent and discord plagued the Donner party from the start of its hazardous
journey. Four men died early on of violence and one of ‘consumption’. In
a dispute over the order of wagons, James Reed, aged 25, killed John Snyder
and was banished, leaving the rest of the Reed family to go on with the
group. Fortunately, the Breen family took in the remaining Reeds and helped
them in the hard times to come. Lost animals, straggling wagons and seemingly
trivial problems extended the journey many days longer than had been planned.

These delays brought disaster upon the pioneers’ heads. Trapped by heavy
snowfalls in late October of 1846, the increasingly desperate group was
forced to pass the winter on the eastern flank of the Sierra Nevada mountains.
In late December, 15 members of the group decided to risk completing the
journey on foot, shod in snowshoes; only seven of them survived. Those people
who had stayed behind in the mountains slowly starved, as is vividly portrayed
in their diaries. They ate all their food, then killed and devoured their
draft animals, and finally consumed their family pets. ‘We lived on little
Cash for a week,’ wrote 13-year-old Virginia Reed of her dog.

When the pets were gone, the people boiled hides, fur rugs and picked-clean
bones to make a gelatinous sort of soup. As a last resort, they ate their
own dead with increasing sang-froid, as shown in this diary entry: ‘Mrs
Murphy said here yesterday that she thought she would commence on Milt and
eat him, it is distressing. Sat 27th beautiful morning.’

By the time the last survivor was rescued on 21 April 1847, 40 of the
original 87 had died. There are suspicions, although never proven, that
the demise of some of those 40 had been hastened along.

Part of the fascination of the story is the fine line between the tragedy
that happened and the safety that was almost there to be had. Only five
days ahead of the Donner party another group had left Fort Bridger, Wyoming,
and made it safely through the mountains. Had the Donner party left a little
earlier – or perhaps followed the more northerly California Trail rather
than the Hastings Cutoff to the south of the Great Salt Lake – they might
have survived with relatively few losses. Instead, theirs was a catastrophic
failure, one recorded graphically in the doomed pioneers’ diaries.

‘It is not often that a tragedy is recorded in such detail that you
can test the relationships predicted on theoretical grounds,’ Grayson says.
Conveniently, the name, gender and relationship to other members of the
party are known from the diaries and records kept by several of the party;
ages are also known, or can be estimated, for all with the exception of
one married couple, the Wolfingers. In all, 87 individuals, ranging from
six babies aged one year to three men in their 60s, left Springfield, Illinois,
in April of 1846. An additional elderly woman who left with the party died
of pneumonia almost immediately, and so is not counted as a member of the
group.

Grayson’s first question was whether this party mirrored the society
from which it was drawn: the answer was ‘no’. Compared to contemporary census
data from Illinois, the composition of the Donner party was skewed. There
was a disproportionate number of men overall (some 70 per cent), especially
between the ages of 20 and 39 – a bias that was typical of emigrating groups
during this period. Thus, as Grayson observes, ‘they didn’t look so much
like the population they were coming from as the agrarian population they
were going to’.

There was also a shortage of individuals aged between 15 and 19, which
was compensated for by an excess of those aged between 20 and 29. Again,
this probably reflected the nature of the group as a party of adult (but
mostly young) males and their families who were emigrating in search of
a better life.

More to the point, Grayson wanted to test the fate of the Donner party
against specific predictions based on demographic studies of human mortality
in general. Three factors – age, gender and social ‘connectedness’ – are
generally considered to be important predictors of survival. All other factors
being equal, demographic studies would predict high death rates for those
in very young and very old age classes. Evidence also suggests that more
men would die than women, regardless of age. Individuals with smaller social
networks also seem more vulnerable than those with larger ones.

How did these predictions fare? Rather well. For example, exactly as
predicted, the youngest and oldest emigrants in the Donner party experienced
great difficulties. Of the 16 children under five, only 6 (37.5 per cent)
survived. Even after the rescue parties arrived, extreme youth was a hazard.
When the rescuers finally reached the depleted band, 45 people attempted
to walk out of the encampment with them; 38 survived. Five of the seven
individuals who died at this stage were 12 years old or less. Similarly,
not one person over 49 years of age lived. Selection by age might be considered
the first and most potent predictor of mortality.

Although extreme youth (or age) was a disadvantage, relative youth paid
off for the group as a whole. Grayson found that those who survived were
on average 7.5 years younger than those who perished. In other words, apart
from very small children, younger individuals were apparently stronger and
better able to resist the hardships than older ones.

Selection by age did not explain everything, however; gender had a potent
affect on survival, too. Women fared better than men: only about 30 per
cent of the women died as opposed to 57 per cent of the men. Because the
diaries revealed the timing and sequence of deaths, Grayson was able to
show that men died earlier during the five-month ordeal than women. Of those
who reached the wintering-over camp, more than half of the men died in the
first two months, whereas no women died until the last three months.

Surprisingly, a high proportion (66.6 per cent) of males in their prime
– between the ages of 20 and 39 – died. Logically, these individuals should
have been the strongest and most physically fit members of the party. Here,
the third variable, size of kinship group, apparently became crucial. Men
in this age group who lived had an average of 4.6 relatives in the party;
those who died had only 2.1 kin on the trip. Indeed, male survivors of all
ages had more social connections than non-survivors.

Probably, the women’s high rate of survival can be partly explained
by the size of their kin groups, too. Understandably, given the social mores
of the era, all females travelling in the party were related by birth or
marriage to other group members, whereas 15 males were ‘unattached’. Nearly
all these male loners (13 individuals or 87 per cent) died. In short, females
had consistently larger kin groups on average and consistently higher rates
of survival than males.

The significance of an extended support group in times of extreme hardship
is made very clear by the grim figures from the Donner party. The two families
that banded together, the Breens and the Reeds, actually managed to bring
their respective groups of nine and six individuals through the ordeal intact.
This was an amazing accomplishment since both families had children aged
5 or less and both included a substantial proportion of males. James Reed,
the man who had been expelled from the group for murder, led one of the
first rescue parties.

Other sizeable kin groups, such as the 16 Donners, the 12 Fosdicks and
Graves, or the 13 combined Foster-Murphy-Pike family, kept about half of
their members alive. None of the smaller kin groups fared better than this,
except for the two lone men, William Herron (aged 25) and J. B. Trubode
(aged 23), who lived.

How do social connections benefit people subjected to such hardships?
The answers may lie as much in psychological factors as in pragmatic ones.
Certainly, groups comprised of individuals with strong emotional and kinship
ties may tend to ‘look after their own’, sharing food and water and seeing
that weaker members of the group are cared for. But it may be as important,
in times of extreme stress, to have the emotional support and warmth of
a social group to help to maintain optimism, establish a sense of normality
and sustain the will to live. Lone individuals would be far more vulnerable
to feelings of hopelessness which might lead them to abandon the fight to
stay alive.

Poignantly, kinship had its down side, too. One woman, 45-year-old Tamsen
Donner, died because she refused to leave her ailing, 62-year-old husband,
George Donner, in the camp. She turned down the chance to go with a rescue
party that left in mid-March because he could not travel. She appeared to
be in good health then and may have hoped that they could both endure until
another, easier chance to escape presented itself. But both died before
the last rescue in late April.

The moral of the story? Grayson’s analysis showed that simple demographic
factors did predict survival under stressful conditions. Before the study,
Grayson had an idea how it might turn out. Based on his personal field experiences
– trivial difficulties compared to what the Donner party suffered – Grayson
had begun to wonder if women coped with open-ended, possibly serious problems
better than men.

‘If something happens, like a vehicle gets stuck and you need some short-term
aggression to get it out, men do much better,’ Grayson says. ‘But if I’m
going to be stuck for maybe two or three days, waiting for someone to come
and get me out, I’d rather be with women than men. The lack of control,
the inability to do anything bothers everyone, but somehow women seem to
calm down and take it better.’ Studying the Donner party confirmed his intuitions:
‘This study showed pretty clearly that, physiologically or psychologically,
females do survive cold, stress and famine better than males.’

Put another way, Grayson’s work can be taken as a word to the wise:
any man thinking of emigrating under risky conditions would do well to take
along his mother, his sisters, his wife and her sisters, if he can persuade
them all to come.

And, in the words of Virginia Reed, ‘Never take no cut offs and hurry
along as fast as you can.’

Pat Shipman is a freelance science writer based in Maryland.