David E. Davis (ecologist)
David E. Davis (July 18, 1913 – October 31, 1994) was an ecologist and animal behaviorist noted for being the "founder of modern rat studies". Early life and education 
Davis was born in Chicago and raised in Wilmette, Illinois. He received a Bachelor of Arts degree from Swarthmore College in 1935, then a Master of Science and PhD at Harvard University in 1939. Davis completed a postdoctoral fellowship at the University of Chicago, where he studied the behavior of chickens under L. V. Domm. Career 
From 1941 to 1943, Davis investigated the hosts of yellow fever in Brazil for the Rockefeller Foundation. He also spent two years studying typhus in Texas. For 13 years, Davis worked as an assistant professor at the Johns Hopkins School of Hygiene and Public Health, where he started the Rodent Ecology Project. Through systematic research, he debunked the myth that there was one rat per person in New York City and placed the rat population at around 250,000. Davis also researched the spread of the bubonic plague through rodents. He later became a professor at Pennsylvania State University, then chairman of zoology at North Carolina State University. During his career, he published three books and 230 papers. References 

1913 births
1994 deaths
American ecologists
Swarthmore College alumni
Harvard University alumni
Pennsylvania State University faculty
North Carolina State University faculty
Johns Hopkins University faculty
People from Wilmette, Illinois
People from Cook County, Illinois