Before Europeans colonized North America there were 30+ million bison roaming the plains. Today, we have have 30 million beef cattle. People make it out to be like the scale is unnatural but Mother Nature is quite capable of scale herself.
The key thing here is that those bison were eating grasses and leafy greens from the wild, not from extensive grass and grain farming operations (all of which largely exclude other plant, animal, and insect life). 30 million bison roaming and grazing makes sense, but sustaining them largely off of conventional farm outputs isn't the same thing.
