||V. Smil, Should we eat meat?, Wiley-Blackwell, 2013 p.149 bottom paragraph
||Smil V. Harvesting the biosphere: the human impact. Popul Dev Rev. 2011 37(4):613-36.PubMed ID22319767
||Value arrived at by dividing 600 million tons of live weight (see comments section below) by the human population on earth (~7E+9 people) equaling 86kg/person.
||"Using these totals and appropriate average body weights, [Smil] calculated
that this domesticated zoomass rose from at least 170 Mt of live weight
in 1900 – when it was more than four times larger than that of all wild
terrestrial mammals – to at least 600 Mt of live weight in the year 2000
when it was approximately 25 times the mass of all wild land mammals