US Geological Survey



David L. Mech

Date of this Version



U.S. Geological Survey Circular 1422, 255 p.


Published in Perry, M.C., ed.


The gray wolf (Canis lupus) was one of the first species placed on the Endangered Species List in 1967. The Endangered Species Act of 1973 legally protected the wolf along with other listed species. Patuxent Wildlife Research Center (Patuxent) in Laurel, MD, began its Endangered Wildlife Program in 1966, and U.S. Fish and Wildlife Service (USFWS) biologist Ray Erickson was assigned to lead it. In 1973, I was transferred to the program from Region 3 of the USFWS, having been employed there since 1969 to study wolves in Minnesota. Endangered Species Act protection of the wolf fostered its quick population response, and wolf numbers began to increase in their reservoir in northeastern Minnesota and adjacent Canada and expand throughout northern Minnesota and eventually into Wisconsin and Michigan. In 2009, the number of wolves in Minnesota was approximately 3,000, and there were at least 1,500 in Wisconsin and Michigan. This chapter describes Patuxent’s wolf research, which continued into 1993 when Congress incorporated the USFWS’s Endangered Wildlife Research Program into the National Biological Survey (NBS). Eventually the NBS merged with the U.S. Geological Survey, and the long-term wolf research program was transferred to the Northern Prairie Wildlife Research Center. Through all the administrative changes, Patuxent’s wolf research project continued through the various agencies into the present (2016).