Davis was born in Rockford, Illinois and was educated at North Central College, Naperville.
In 1930, he joined the Chicago Natural History Museum as an assistant in osteology under Wilfred Osgood.
He took a special interest in identifying the evolutionary relationships of the giant panda to other mammals using anatomical studies.
He took over 25 years on the study and published a comprehensive book on the topic just a couple of months before his death.
[1] Along with Rainer Zangerl, he was involved in translating Willi Hennig's influential work on phylogenetics into English which was published in 1966.