Ursula Cowgill

Ursula M. Cowgill is a biologist and anthropologist who worked for Yale University , Dow Chemical Company and the University of Colorado during the second half of the 20th century. Her work includes studies of agricultural practices in pre-Columbian Mesoamerica, seasons of birth in human beings, the relationship between cultural gender bias and infant mortality, and the possible role of selenium in reducing mortality from AIDS. She also looked after four pottos for many years and published a series of observations on their behaviour.

Cowgill earned a PhD from Iowa State University in 1956. Later she worked as an analytical chemist for the limnologist G. Evelyn Hutchinson. Her first journal articles, some published jointly with Hutchinson, appeared in the early 1960s.

Cowgill was living in Colorado as of 2003. In addition to her scientific research, she is an activist with the American Civil Liberties Union.

Additional recommended knowledge

What is the Correct Way to Check Repeatability in Balances?

Essential Laboratory Skills Guide

How to ensure accurate weighing results every day?

Work and findings

Pottos

In 1959, three pairs of pottos from West Africa arrived at Yale's Osborn Zoological Laboratory. At first they lived in the laboratory with a number of other nocturnal prosimians that Cowgill and Hutchinson were studying. In 1964, Cowgill took two of the pairs to live with her. She looked after them until 1981, when she gave the sole surviving male to a colleague.

While the pottos were with her, Cowgill published a number of journal articles on their anatomy, diet, reproduction, illnesses and recovery, and social behaviour. These publications constitute one of the few long-term studies of pottos in captivity.

Maya agriculture

Between 1961 and 1963, Cowgill and Hutchinson made studies of soil in the Petén Basin, Guatemala, with the aim of learning about the effects of agricultural practices of the pre-Columbian Maya civilization. Their findings reported that Maya cultivation methods had gradually robbed the soil of vital elements, meaning that it eventually became unable to sustain crops. Some scholars have linked this exhaustion of the soil to the 10th century decline of the Maya urban settlements in the Petén region.

Sex ratio and childhood mortality

Cowgill's research into gender and child mortality covered both historical records in England and contemporary observations in Guatemala. Using birth and death records from the parish registers of York between 1538 and 1812, Cowgill found that throughout the city's history, girls at every stage of childhood had died at a higher rate than boys of the same age. This resulted in an adult sex ratio of 136 males for every 100 females. Cowgill theorised that this was partly because girls were more likely to be victims of infanticide, and partly because sons tended to receive better feeding and care than daughters.

In Guatemala, Cowgill studied an indigenous village where the sex ratio was even more skewed -- 178:100. Cowgill observed that mothers in this village breastfed sons for much longer than daughters, and tended to give them preferential treatment even after weaning. Cowgill and Hutchinson also speculated that the sexually provocative behaviour of young girls in this village might be a survival mechanism.

Seasons of birth

Cowgill undertook one of the first scientific studies of seasonality in human reproduction. Taking data from historical records and indigenous peoples in various countries, she concluded that conception and birth in human beings, like that of many other animals, followed seasonal patterns to a degree. Because the pattern was different in the Northern and Southern Hemispheres, Cowgill hypothesised that weather was the determining factor. However, she found that in urbanised and industrialised areas the pattern had been disrupted. Her 1966 article on the topic, published in the journal Ecology, has formed the basis for subsequent research by other scientists.

Selenium and AIDS

In 1997, Cowgill gauged the selenium content of soil in various locations in the United States by measuring the amount of the mineral that was absorbed by alfalfa. She then correlated this information with the mortality rate of AIDS in the area. She found that the more selenium there was in the soil, the lower mortality from AIDS was. The relationship was especially strong among African-Americans.

Publications

• 'An apparent lunar periodicity in the sexual cycle of certain prosimians' (with Alison Bishop, R.J. Andrew and G.E. Hutchinson). Article published in Zoology journal, December 1961.
• Bajo de Santa Fe (with G.E. Hutchinson). Book, 1963.
• 'Sex ratio in childhood and the depopulation of the Peten, Guatemala' (with G.E. Hutchinson). Journal article, February 1963.
• 'Season of Birth in Man. Contemporary Situation with Special Reference to Europe and the Southern Hemisphere'. Article published in Ecology journal, June 1966.
• The history of Laguna de Petenxil, a small lake in Northern Guatemala. Book, 1966.
• 'Heat transfer solely by molecular conduction in the metalimnion' [1]. Article published in Geophysics journal, December 1966.
• 'The people of York, 1538-1812'. Scientific American, January 1970.
• 'A myeloliposarcoma in a female Perodicticus potto: mineralogical and elemental chemical analysis' [2]. Journal article, 1977.
• 'Elemental analysis of a tumor from a nocturnal prosimian with special emphasis on bromine' [3]. Journal article, January 1977.
• 'Normal blood values of an adult male Perodicticus potto with comparative data from other primates' [4] (with L.B. Zeman). Journal article, 1980.
• 'The tellurium content of vegetation' [5]. Journal article, September 1988.
• Aquatic toxicology and hazard assessment, 12th volume (with Llewellyn R. Williams). Book, 1989.
• 'The reproducibility of the three brood Ceriodaphnia test using the reference toxicant sodium lauryl sulfate' [6] (with D.P. Milazzo and B.D. Landenberger). Journal article, July 1990.
• 'The response of the three brood Ceriodaphnia test to fifteen formulations and pure compounds in common use' [7]. Journal article, July 1991.
• 'Variation in the nitrotoxin concentration of 13 species of Astragalus (Fabaceae) over a 6-year period' [8] (with D.P. Milazzo). Journal article, November 1991.
• 'The distribution of selenium and mortality owing to acquired immune deficiency syndrome in the continental United States' [9]. Journal article, January 1997.