The Bison of Yellowstone National Park
Meagher MM. 1973. The Bison of Yellowstone National Park. National Park Service Scientific Monograph Series. No. 1. National Park Service. Washington, D.C.
Objectives of this study were to provide basic data on the life history, habits, and ecology of bison in Yellowstone National Park. The original population of bison in historic times consisted of mountain bison, Bison bison athabascae. In spite of poaching to near-extermination by about 1901, a remnant of the subspecies survived and increased. Interbreeding with a population of plains bison, B. b. bison, introduced in 1902, began by the 1920's. The present bison population consists of hybrid descendants of the two subspecies. The present wintering distribution within the park approximates that of the historic population, occurring in the three subunits of Lamar, Pelican, and Mary Mountain, none of which are geographically isolated from the others. The present summering population approximates the historic distribution only in the Upper Lamar-Mirror Plateau and Hayden Valley areas. A large west-side and a large northern summering population are lacking. Present (1968) numbers are half or less than those of probable historic numbers.