# Ursula Cowgill

Ursula Moser Cowgill (9 November 1927 – November 27, 2015) was 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 was an activist with the American Civil Liberties Union.

## 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

* Cowgill, U. M.; Bishop, A.; Andrew, R. J.; Hutchinson, G. E. (1962). "An Apparent Lunar Periodicity in the Sexual Cycle of Certain Prosimians". Proceedings of the National Academy of Sciences of the United States of America. 48 (2): 238–41. Bibcode:1962PNAS...48..238C. doi:10.1073/pnas.48.2.238. JSTOR 71188. PMC 220764. PMID 16590923.
* Bajo de Santa Fe (with G.E. Hutchinson). Book, 1963.
* Cowgill, UM; Hutchinson, GE (1963). "Sex-ratio in childhood and the depopulation of the Peten, Guatemala". Human Biology. 35: 90–103. PMID 14023537.
* Cowgill, U. M. (1966). "Season of Birth in Man. Contemporary Situation with Special Reference to Europe and the Southern Hemisphere". Ecology. 47 (4): 614–623. doi:10.2307/1933939. JSTOR 1933939.
* The history of Laguna de Petenxil, a small lake in Northern Guatemala. Book, 1966.
* Cowgill, UM (1967). "Heat transfer solely by molecular conduction in the metalimnion". Proceedings of the National Academy of Sciences of the United States of America. 57 (2): 198–200. Bibcode:1967PNAS...57..198C. doi:10.1073/pnas.57.2.198. PMC 335487. PMID 16591451.
* Cowgill, UM (1977). "A myeloliposarcoma in a female Perodicticus potto: Mineralogical and elemental chemical analysis". Journal of Medical Primatology. 6 (2): 114–8. doi:10.1159/000459730. PMID 406401.
* Cowgill, UM (1977). "Elemental analysis of a tumor from a nocturnal prosimian with special emphasis on bromine". The Science of the Total Environment. 7 (1): 63–9. Bibcode:1977ScTEn...7...63C. doi:10.1016/0048-9697(77)90017-1. PMID 402025.
* Cowgill, UM; Zeman, LB (1980). "Normal blood values of an adult male Perodicticus potto with comparative data from other primates". Folia Primatologica. 33 (4): 273–90. doi:10.1159/000155942. PMID 7419137.
* Cowgill, UM (1988). "The tellurium content of vegetation". Biological Trace Element Research. 17: 43–67. doi:10.1007/BF02795446. PMID 2484368. S2CID 10819388.
* Aquatic toxicology and hazard assessment, 12th volume (with Llewellyn R. Williams). Book, 1989.
* Cowgill, UM; Milazzo, DP; Landenberger, BD (1990). "The reproducibility of the three brood Ceriodaphnia test using the reference toxicant sodium lauryl sulfate". Archives of Environmental Contamination and Toxicology. 19 (4): 513–7. doi:10.1007/BF01059069. PMID 2386407. S2CID 29347853.
* Cowgill, UM; Milazzo, DP (1991). "The response of the three brood Ceriodaphnia test to fifteen formulations and pure compounds in common use". Archives of Environmental Contamination and Toxicology. 21 (1): 35–40. doi:10.1007/BF01055553. PMID 1898115. S2CID 34093998.
* Cowgill, UM (1991). "Variation in the nitrotoxin concentration of 13 species of Astragalus (Fabaceae) over a 6-year period". Biological Trace Element Research. 31 (2): 111–8. doi:10.1007/BF02990419. PMID 9438032. S2CID 1400765.
* Cowgill, UM (1997). "The distribution of selenium and mortality owing to acquired immune deficiency syndrome in the continental United States". Biological Trace Element Research. 56 (1): 43–61. doi:10.1007/BF02778983. PMID 9152511. S2CID 11350156.