“There were observed buffalo herds that took 2-3 days to pass by the settlement along the Muskingum River.”
~Moravian missionaries, Ohio Valley, 1740s
Overall, CH4 emissions from bison, elk, and deer in the presettlement period in the contiguous United States were about 86% (medium bison population size) of the current CH4 emissions from farmed ruminants in the United States (Table 1). If the high bison population estimate is considered for this comparison, wild ruminants in the presettlement period emitted about 23% more CH4 from enteric fermentation than the current domestic ruminants in the United States.
Exploring the influence of ancient and historic megaherbivore extirpations on the global methane budget
by Felisa A. Smith, John I. Hammond, Meghan A. Balk, Scott M. Elliott, S. Kathleen Lyons, Melissa I. Pardi, Catalina P. Tomé, Peter J. Wagner, and Marie L. Westover
Credit: Frank Mitloehner (see discussion thread on Twitter)