With the arrival of the Spaniards in the 16 ^th century, the cultivation of henequen fiber became a mass industry that flourished in the mid-19 ^th century ( Rioux, 2014). There were many haciendas (large agricultural estates or plantations) in Spanish-speaking countries, especially in Mexico, and from the mid-18 ^th century these grew in size and economic power for almost a hundred years. In the Yucatan region of Mexico, the haciendas started as maize and sugar plantations, but later they became henequen estates.

The haciendas were independent organizations employing hundreds of workers, arranged according to a certain structure. The most important in the hierarchy were the landowners, then the haciendados (people to whom the land was gifted along with peons - unskilled farm workers), at the bottom there were Maya people ( Kumar, 2019). Haciendas were typically composed of a variety of different structures, including a main house, a kitchen, a warehouse, servant quarters, worker housing, stables, a church, a store, a cemetery, a pigsty, roping areas, gardens or fields, and even prisons. It maintained huge fields of henequen, tended by hundreds of men. The main house, or Casa Principal, was usually the largest building, where the haciendado kept his living quarters and where most of the administration occurred ( Kumar, 2019; Wells, 1985). Plants had machines to produce henequen fibers and ropes which were shipped worldwide from the port of Sisal ( Kumar, 2019).

From the end of the 19 ^th century to the 1920s, for around 40 years, henequen was the basic industry of Yucatán. This resulted in Yucatán becoming the richest state of Mexico ( Brannon & Baklanoff, 1987). By this time, the henequen plant was called “green gold”. But henequen had been present in the life of Mayan society since pre-conquest times. The plant was often grown outside of houses, along roads and outside of towns ( Rejón, 2006). A major use for the henequen fiber was rope to fasten and pull, and as material for sandals, hunting bows and traps, roofing thatch, fishing nets, hammocks, bags to transport different items (e.g. corn seed) or other framing tools to cultivate milpas (fields cleared of forest where farmers plant more than a dozen plants at once, including corn, avocado, many varieties of squash and bean, melon, tomatoes and the like). Henequen fiber was also used to drill teeth, and the sharp spines of henequen leaves were used as needles. In addition, prisoners of war were bound with henequen rope, juices from Agava were used to make wine, and henequen also could be a decoration ( Rioux, 2014).

The henequen industry was owned by homogeneous groups called the ‘elites’. They were most often white individuals of Spanish origin who came from two categories: either they were born in Creole families and most often they were already wealthy, or they used the export and import of henequen to create new wealth ( Rioux, 2014). In 1856, as a result of reform laws, the lands belonging to the villagers were divided, the ‘elites’ quickly bought land from Mayas and changed that land from subsistence food farming to henequen production. Unfortunately for Maya people, selling their land was the only way to earn some money and support their families ( Evans, 2012). However, soon after selling their land most Maya adults became henequen plantation workers. As already mentioned, many ‘elites’ were successful in the henequen industry, but there were 20 to 30 families known as ‘ casta divina’ (divine caste), who controlled 80-90% of the henequen industry ( Riestra, 1996).

Life on haciendas for workers was very hard. Haciendas became the places in which the Mayas lived, worked and shopped. Maya families often spent their lives on the plantations for many generations ( Peniche Rivero, 2003). We use the term ‘ henequeneros’ for individuals (often belonging to ‘elites’) that supervised the production of a henequen in a given hacienda and oversaw the Maya families working there. The role of henequeneros was to encourage workers to remain in the hacienda. Also, marriages outside the hacienda were often forbidden. Everything was done to bring families together in order to control the social life of Maya peasants ( Joseph, 1982; Remmers, 1981; Wells, 1985).

Workers were offered loans by henequeneros that were part of the so-called ‘paternalistic goods’ (restriction of the freedom of a person or group of people). This concerned the land of milpa, corn ration, access to water, medical care, and sometimes children’s education. For hacendados (persons who own or supervise haciendas), control over the Maya people provided year-round labor. It was also a certain protection for the workers, but the possible benefits amounted to the loss of autonomy, backbreaking year-round labor, and separation from traditional pueblo life. Thus, henequen workers were essentially slaves as a result of the debt peonage system (an employer compels a worker to pay off a debt with work) ( Alston et al., 2009). Even though elites claimed that workers had the right to leave haciendas, realistically, they were accumulating huge debts and were unable to escape. In 1900, rural laborers were spending half to three-quarters of their incomes on basic staples of life, mainly food ( Buffington & French, 2000). Their daily food typically consisted of two tortillas, a bowl of beans, and a plate of fish ( Sterling, 2012). Although hacienda owners claimed slavery was non-existent, their rules and practices bear strong resemblance to a slave society. The workers were forced to buy food and other things at the hacienda-owned store. The store provided credit, and this indebted the Maya to the hacienda. They were slaves because they could not leave the hacienda until they paid their debt, but they could never do this ( Rioux, 2014).

In Yucatán at this time, education was devoted to the expansion and success of the henequen industry, and as a result, laborers were mainly trained in henequen production only. However, other residents in Yucatán experienced an expansion of education, and secondary and professional education did advance. In 1857, there were 21 public primary schools with less than 2,000 students, but by 1883, there were 225 schools with over 8,000 students. Despite all of the increases in education, many people in Yucatán were illiterate and the literacy rate was still low due to the many laborers on haciendas ( Remmers, 1981).

Health problems and injuries were prevalent on the haciendas, but workers did not have access to medical treatment ( Remmers, 1981). Henequen is a rough, spiny plant, and its continued contact with skin often caused irritation and eczema among laborers. The challenging manual labor led to many fractured or broken arms and legs. In addition, carrying henequen leaves in the sun and the heat in Yucatán was especially grueling ( Remmers, 1981). Additionally, public health agents ignored hacienda conditions and doctors were rarely present. Despite the modernization efforts in society, healthcare on haciendas was virtually non-existent, so modernity was mainly limited to spaces outside of the hacienda system. Conditions were unsanitary, and diarrhea was the leading cause of death, especially among infants. Poor diets and the lack of sufficient food led to starvation for many laborers, and suicide was not uncommon. Doctors and medicines were only present on larger haciendas, and even then, they were not sufficient to treat the quantity of health issues faced by laborers ( Ransom Carty, 2006; Remmers, 1981; Wells, 1985).

Laborers were required to wear specific types of clothing and they were not allowed to wear foreign styles. Also, workers and their families were required to cut their hair a certain way ( Moseley, 1980).

There are many factors that contributed to the decline of the henequen industry, but the changes brought about by the Mexican Revolution were crucial in causing the era of poverty in Yucatán ( Evans, 2012; Rioux, 2014). The Mexican Revolution arrived in Yucatán in 1915, five years after it had begun in Mexico City. Laborers experienced slave conditions, and the revolutionaries sought to give them more rights. Between August 1915 and February 1917, the cost of production of henequen fiber increased by more than double due to the increase in wages for workers. These changes were positive for laborers, but henequeneros were forced to pay higher wages and provide more services to the workers. The only reason henequen continued to prosper was the massive demand created by World War I. The further instability in Yucatán and increased prices of henequen encouraged the United States to continue seeking different sources of fiber. However, elites in Yucatán continued to invest only in henequen, which led to an increase in poverty, because henequeneros could no longer pay the workers' debts. After the 1920s, the henequen industry faced continued challenges. The Great Depression continued to affect society, which reduced the demand for wheat and henequen. During the 1930s, adverse weather changes, such as drought, windstorms, cold winters, hot summers, as well as grasshoppers, caused further damage to the wheat industry. Between 1934 and 1940, large areas of land were redistributed, which resulted in the confiscation of 61% of henequen fields. Yucatán became one of the poorest states in Mexico and could not survive without the help of Mexico City ( Evans, 2012; Rioux, 2014). During the 1960s, there was an attempt to revive the henequen industry, but hard fiber industries had already been established in other areas, and it would have been very challenging for Yucatán to become competitive in the market again ( Carrillo, 2013). However, it should be mentioned here that the Mexican Revolution also brought many positive changes to Yucatán as it ended the slave work conditions and gave more rights to laborers. It also created thousands of schools, health reforms, and sanitation services ( Rioux, 2014).

The women on henequen haciendas had few rights and were under the control of both their husbands and overseers. It was also not uncommon for husbands to beat their wives. While workers were treated like slaves, their wives often experienced the effects of their anger and frustration in the form of violence mainly because of failures in their work. They also worked very rarely in the henequen cultivation, but if they had to work, they were not paid for their work. Thus, the women stayed mostly at home ( Wells, 1998).

Their household responsibilities include preparing food, collecting water and firewood, making hammocks, etc. They were also expected to reproduce to provide for the next generation. Women were also sexually abused. There was a known "ritual of the first night" in which a henequenero or overseer rapes the wife or daughter of a worker to show who has the greatest power in the hacienda ( Wells, 2006).

The literature contains much information about Maya life in the second half of the 20 ^th century, including their population size, households, work, income, crops, culture and education ( Lutz et al., 2000). It is worth noting that the life of the Maya has not changed significantly since the fall of the henequen economy. However, they were somewhat independent in this time, able to cultivate milpa (corn, beans and squash), usually in small fields, and leave their place of residence looking for work anywhere, e.g. in the nearby holiday resorts of Cancun or Merída.

The authors of the present paper spent 13 years in Yucatán, mainly at the end of the 20 ^th century, taking part in various research projects which took place in Merida (the capital city of Yucatán), Progreso, Sotuta, Yaxcabá Municipality, and villages near Chichenitza, such as Pisté where the Steggerda research took place ( Steggerda, 1932; Steggerda, 1941; Steggerda, 1977). Observations of these communities by the authors has led to the following reflections about living conditions:

The households (farms) are different, depending on the size of the family and its wealth. Every nuclear family, consisting of parents and at least one child, has its own home. Such a family also has its own or shared garden, kitchen, storage area, and sometimes manufacturing area. The number of shared buildings in a household depends on how many families are living there.

The Yucatán Peninsula has year-round warm weather and is often hot and the style of home offers a cool place to live. The shape of the houses has been similar from generation to generation. The differences between houses are the size and the materials used to build them. The appearance of the houses also vary depending on the village in which they were located. Many houses are built of wooden stakes ( Figure 1 and Figure 2), but there are also houses with a more solid construction. Most houses are about the same size. Often the front door is lined up with a backdoor or window to create cross ventilation, which keeps the home cool. The floors are often concrete and keep the house fresher since the slabs are on the ground. The houses are oval in shape with thatched rooves, which are waterproof when laid in a continuous pattern. Some houses consist of mud and stone walls with thatched roofs, and some are also covered with concrete, grass, or palm leaves (which is very expensive). A thatched roof does not absorb the heat like concrete, so that makes it cooler. Backyards are often full of fruit trees, vegetables, herbs and useful things for the family’s meals. There are also chickens, pigs, ducks, or turkeys.

Most people have two houses. One is for living and the other is for cooking. This prevents the living space from getting smoky or catching fire. The fire is low, surrounded by stones, or against a concrete wall. Most of the cooking is done on a comal for making tortillas or pots for cooking in ( Figure 3). Every house contains some type of pottery. The ancient Maya used pottery for cooking, eating, and storing water. The interior furnishing of houses for living is limited mainly to the space needed to hang hammocks used for sleeping. It is not common to store a lot of food in the home. The staple food of corn is mainly kept in the field. Also, Maya houses have no furniture. Necessary items are hung in plastic bags, including food. In recent times, however, refrigerators, TV's and other conveniences have been found there; for example, the authors have often seen a poorly constructed house where there were at least two TV's, a car with an incomplete body and a huge refrigerator.

Women spend the majority of time not only at home taking care of the children, but also are in charge of gardening and sometimes help men in farm work. Maya women’s dress is very specific and they try to wear it on every occasion ( Figure 4). The men take care of the family by mainly cultivating the milpa, hunting and providing other food for the family.

As previously mentioned, the 20 ^th century included many economic crises, but overall socio-economic conditions improved. These changes are especially interesting when we relate them to the biological status of the Maya Indian populations before the collapse of their high civilization which took place between the 8 ^th or 9 ^th centuries and was probably caused by a combination of deforestation and drought ( Stromberg, 2012). The retardation in growth and maturation of Yucatecan populations during the 19 ^th and 20 ^th centuries has been observed ( McCullough, 1982; Saul, 1972; Starr, 1902; Steggerda, 1941). There are only two publications on secular changes of body height in the Yucatán. The first one describes the lack of changes in men born between 1860 and 1933 ( McCullough, 1982), the second one describes small changes between 1933 and 1956 ( Wolański et al., 1994). It should be added that based on skeletal measurements from archaeological excavations from preclassic (2500 BCE-250 CE), classic (250-900 CE) and postclassic (900-1521) periods, and then based on measurements on living people, it can be concluded that Maya Indians experienced a decrease in body height. From the second half of the 19 ^th century to the first half of the 20 ^th century, stabilization of body height was observed. In the last 60 years a slight increase in body height has been observed in children, which affects the final height in adults ( Wolański & Siniarska, 1999).

Globally, Maya people have one of the shortest statures. The average height of contemporary, rural-living Maya men and women in Mexico and Guatemala is 160 cm and 148 cm, respectively ( Bogin et al., 2014). Maya adults and children measured in the early to mid–20 ^th century were usually thin, with very low body fat. Short stature and thinness were probably associated with an inadequate diet ( Bermudez et al., 2008; Bogin, 2013). Their diet lacked nutrients needed for growth and they also suffered from respiratory and gastrointestinal infections ( Bogin, 2013).

On the basis of the presented characteristics of the Maya living conditions in Yucatan from the beginning of the 20th century to almost the end of the 20th century, the aim of this study is to assess the direction and the level of living condition changes.

This assessment is built on a comparison of changes in height with age in both sexes, changes in SDI, and changes in women’s age of maturation. Changes in height (secular trend) with the age of the studied individuals indicate how each sex reacts to the living conditions existing in a given period of time. Changes in SDI indicate what are the differences in body height between men and women for each age cohort, which is considered a manifestation of specific living conditions. This index is used in the absence of information on the living conditions of adults at the time of the interview. In addition, one of the many indicators of changes in biological status is the age of maturation. Data on age at menarche will therefore also be considered.

Permission to conduct the study was sought and given by CONACyT (Consejo Nacional de Ciencia y Tecnología). Verbal informed consent was obtained from all participants to participate in the project. Before taking part in the project, the participants were informed of what would be required of them, that participation was voluntary, and that they could withdraw at any time. Verbal consent was obtained over written consent because not all participants taking part in the project were literate. Verbal consent was documented by the project team, and the number of participants that took part or were excluded for various reasons was recorded. The original project protocol included that verbal consent would be obtained, and this mode of consent was therefore permitted by CONACyT.

A cross-sectional study including Merida and vicinity residents (Yucatán, Mexico) was performed.

The sample included 364 men and 320 women between 20–98 years of age and the study took place from February to November 1994.

Estimating the number of samples was needed to optimize costs of the project. The research was sponsored by CONACyT, the Mexican government agency, and the funds allocated for this purpose were sufficient for the measurements of all volunteers from a given region who agreed to the research. The research was population based and no a priori hypotheses were formulated. It was more about examining the variation of data parameters with age among the Maya. Independently, we tried to have at least 30 people in each study cohort (for each 10-year-old age range and for each gender), which allows us to freely use different statistical tests.

The research was carried out in 1994, i.e. 27 years ago. Most of the research results have never been published due to the lack of available literature (as in the case of this article). Only the publication of the work by Rioux, 2014 - Honors Theses, allowed the authors to find the relevant literature. Unfortunately, there is no such research in later years in Merida or Yucatan. Some of the existing studies ( Bogin, 2013; Bogin et al., 2014), approaching biological status in many aspects, are mainly based on nutritional status, and still do not bring significant changes in the improvement of the living conditions of the Maya group. Why this situation affects Maya is the main goal of this work.

The concept of this study was to measure people from the most numerous ethnic group of the Merida population. Most of the sample (about 80%) was identified as Maya. The assessment of belonging to the Maya ethnic group was based both on their surnames (two Maya surnames or one Maya surname, as well as on their appearance: short stature, corpulent body structure). Younger individuals worked in different kinds of factories localized in Merida city and vicinity, producing different brands of soft drinks and food products. People surveyed belonged partly to blue-collar workers and were employed to do moderate to heavy physical work (lifting, raising, carrying), while some worked directly on the production line, where the work was monotonous and required a lot of attention. Not only men worked there, but also women. Many women worked in garment factories, built by Americans and for the needs of the American market, which were located in the vicinity of Merida.

Older people, not working, generally parents or grandparents of people working in factories, were measured in their homes. This research was conducted in two, rather poor, districts of Merida (Chuburna and Cordemex), where many individuals as Maya resided. People of very old age, often living in great poverty, were measured in nursing homes.

When examining more educated people who held an executive position or supervised the work of other people, these data were not included in the final research material.

Education level varied from illiterate to those who had not completed secondary school. Income levels varied between 900 NP (new pesos/month) for younger people to 300 NP/Mo for older people at a time before the economic crisis at the end of 1994 when the value of the peso was 1US$ = 3.4 P.

The sample was divided into six age groups by gender: 20–29, 30–39, 40–49, 50–59, 60–69 and 70+ years.

Body height of both men and women were collected, as well as age at menarche for women. The height measurement was performed by persons trained and employed to carry out this research. The same was true for age of maturation questions.

Three phenomena were considered: secular trend in height observed in the cohorts of men and women, sexual dimorphism in height which was useful for the assessment of living conditions for the population studied, and age at menarche.

The secular trend of body height was presented and adjusted for age-associated stature loss after the age of 30 years (0.06 cm / yr) according to Trotter & Gleser (1951).

Sexual dimorphism in height was interpreted using the SDI, which was calculated by the following formula: ( X ¯ Males - X ¯ Females / X ¯ Females) * 100. It has been widely described in earlier publications ( Antoszewska & Wolański, 1992; Siniarska, 1996; Wolański, 2012; Wolański & Kasprzak, 1976).

Age at menarche changes between 10-year-old women’s cohorts were assessed using the Kruskal-Wallis Test.

All calculations were done in Statistica 13.0 ( Dell Inc, 2016).

Figshare: Merida1994-95.csv, https://doi.org/10.6084/m9.figshare.16447350.v1 ( Siniarska & Wolański, 2021).

Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).