I keep hearing about cows and methane output. What are the data supporting the effect on global warming of this? Not hearsay but a comparative scientific report. With billions of humans, I doubt that cattle have the numbers to outperform humans. Some work has been done on insects, but here again, what are the population estimates and the math? Should we eliminate insects too? Man probably ate out the mammoth, horse and some other large mammels in North America. Now we raise cattle, pigs (any data here?), etc. since Man has had animal protein as a large part of his diet for a very long time. Just sign me Carnivore born and bred.