Unusual topic for an engineering site! But I read that there are some people who want to get rid of cattle because of their flatulence. That leads to a wonderment whether there is any data comparing the flatulence of cattle with various other animals including humans; maybe in liters per kilogram of body weight. They could then respond that there are a bunch more humans than cattle, so it's not a fair comparison. Thus we need the total volume of flatulence for several different species. Is this sort of data available anywhere?