By examining skull measurement data of Native American tribes, investigators from North Carolina State University and the University of Tennessee have uncovered further evidence to suggest that environmental stressors contribute to shaping the physical appearance of humans.
The research team, including Dr. Ann Ross, a professor of anthropology at NC State, assessed data collected by Franz Boas in the late 19th century, which looked at the length and breadth of skulls from Native American tribes born between 1783 and 1874. The investigators focused on individuals who were members of the eastern and western bands of the Cherokee tribe.
The team organized the data by year of birth, which they say is a vital piece of information to determine what environmental factors the tribes were exposed to.
For example, the western band of Cherokees were exposed to the Trail of Tears in 1838 and the American Civil War between 1861 and 1865, while the eastern band of Cherokees fled to avoid taking part in the Trail of Tears.
The Trail of Tears is the name for the forced removal of Cherokees from their homeland in southeastern states of the US, including Georgia, Alabama and Florida, to "Indian territory" in the west - present-day Oklahoma.
The purpose of this removal was to "civilize" the Native Americans, who many white Americans feared and resented. American officials, including President George Washington, believed a forced removal would make Native Americans more like white Americans and take part in economic practices, such as individual ownership of land and other property.
In 1838, 7,000 soldiers were sent to initiate the removal process. Cherokees were marched 1,200 miles to their new territory. Along the way, they were exposed epidemic diseases, including Whooping cough, typhus, dysentery and cholera, and many suffered starvation. More than 5,000 Cherokees died as a result.
'Environmental factors affect skull measurements'
Researchers say the Trail of Tears and the American Civil War may have affected the head length of the eastern and western Cherokee bands.
From the data, the research team found that the head length of both males and females of the eastern and western Cherokee bands decreased over time.
In detail, the researchers found there was a steady reduction in head length for males in the eastern band of Cherokees. But females from this band saw a sharp decrease in head length in the late 1830s, when they fled to the Great Smoky Mountains in order to avoid forced evacuation.
In the western band of Cherokees, the team found a similar rate of head length reduction in males and females.
They experienced a sharp decrease from the late 1820s to 1850s. They then saw a short increase in head length, before a sharp reduction in the early 1860s - coinciding with the beginning of the American Civil War.
Dr. Ross says that during tough periods, individuals have less access to required nutrition and are at greater risk of disease. She notes that the team's findings demonstrate the impact that these difficult periods had on the physical growth of the Cherokee tribe.
"The study also contributes to our understanding of how environmental stressors can influence skull measurements, which has value for helping us understand prehistoric cultures, historic populations, and the impact of environmental factors on the health of current populations in the developing world."
This is not the only study to delve into the past to determine how we are affected by environmental factors. Medical News Today recently reported on a study detailing the discovery of a 3,000-year-old skeleton with metastatic cancer, which the authors say could have been caused by exposure to smoke from wood fires.