About a year ago Victoria R. Bricker and Rebecca E. Hill published a really interesting article in Ethnohistory (56:2, p. 227-268). It is called Climatic signatures in Yucatecan wills and death records and it discusses wills and death records as proxy data for climate change during the Colonial period. These records help us to understand the effects of famine and epidemics caused by droughts or hurricanes on a local level. The authors focus on two towns northeast of Merida, Tekanto and Ixil, during the period 1724-1768. These towns have large surviving collections of wills and death records.
The Yucatan peninsula has a dry and a rainy season. There are two maxima during the rainy season: June and September. During El Niño years the Atlantic is colder and generates fewer hurricanes. Less precipitation results in a drought. The opposite effect occurs during La Niña years when warm waters in the Atlantic create several hurricanes. The warm waters also bring rain to sub-Saharan Africa which generates an explosion of desert locusts that soon finish off the plants in that region. In search for new food they travel on air currents to the Caribbean and the Yucatan peninsula.
Since death records peak during certain months during a famine it is necessary to understand the phases of famine in relation to climate patterns. In normal years deaths prevails during two seasons. In January and February the night temperature can be as low as 4-5 degrees Celsius. Old and weak people die from hypothermia and respiratory illnesses. In June there is another peak of mortality, just after the rainy season has begun. The rains carry bacteria from accumulated human wastes to the water table and the cenotes and wells become contaminated. People may die from dysentery at this time. In the past, before grain was imported from abroad during droughts, famines also created a third peak in mortality during July and August.
Although the Maya wills seldom mention the cause of death they can be used to study their differential frequency over time. 373 wills from Tekanto (1724-1759) and 65 wills from Ixil (1765-1768) are being used in this study. However, the wills alone cannot be used to determine the timing and intensity of famines. This is because infants, children and some adults did not produce wills. Wills can be produced long before the death of the testator and wills are sometimes lost. Hence, the number of wills does not indicate how many people died that year. The authors use the death records from the parish registers of the Catholic Church in Merida to check on the reliability of the wills as proxies for famines. Most of the people (85% at Tekanto) left only short formulaic wills, most likely a short time before death and hence they can be used to determine the frequency of death by month.
The years of high mortality in Tekanto and Ixil were 1726, 1747, 1759, 1760 and 1767. The rains failed in 1725 and created a famine that lasted until 1727. In 1726, 74 people died in Tekanto. People died so quickly that the notaries did not have the time to write down the wills for 69 of them. Usually the number of wills and deaths in one year are in close agreement. One way to explain the paucity of wills in 1726 is that the deaths were concentrated to July (13 deaths) and August (32 deaths).
In 1747, 40 adults died as a result of a drought. In 1759 and 1760 a total of 83 people died and 51 of them were children who died during the coldest months. It is believed that there was an epidemic rather than a famine these two years. In 1765, locusts ate the harvest and in the following year a hurricane destroyed the crops. 102 people may have died in Ixil in 1765, half of them being children. In 1766 42 people died to be followed by 34 deaths in 1767. Some of the lowest mortality years (1748 and 1761) followed years of very high mortality. The preceding years killed the most vulnerable people and the survivors were more resilient.
The pattern here is that wills recording high mortality rates during the cold months indicate epidemics. Wills recording high mortality rates during the mid and late summer indicate famines caused by droughts or hurricanes. There is no detectable clustering of deaths in June when dysentery prevails today. The authors believe this has to do with the freshwater lens being thicker in the past, before modern pumping used groundwater for irrigation and industry. The lower population during Colonial times also created less human waste products to be washed into the aquifer during the early rainy season. Another pattern found in the records is that, widow and widower remarriages increased after famines and epidemics.
A word of warning for those Mayanists that quickly jump on the direct historical analogy wagon: As I have mentioned in my earlier posts on climate change in the Maya area, some researchers (primarily Richardson Gill), have projected the modern and Colonial period pattern of climate related settlement strategies during droughts to Prehispanic conditions. Indeed, old and young Prehispanic people most likely died during the cold months, locusts plagued people during the summers. Since the Prehispanic sites were larger than the Colonial ones, dysentery may have been a problem. However, Prehispanic sites lacked the overarching Colonial economic system that depleted the countryside during droughts and made the inhabitants in greater peril than during Prehispanic times.