There were about 30 million bison in North America before we hunted them near extinction. Bison, especially young ones, are prey to wolves and bears. Bison weig

There were about 30 million bison in North America before we hunted them near extinction. Bison, especially young ones, are prey to wolves and bears. Bison weight about 1.5x cows. There are about 100 million cows, and if about 30% of those feed pets the numbers come out similar. There are also pigs and chickens, and depleted river fish/wild fowl populations. Wolves/bears are heavier so the same mass of prey supports a smaller population. Still, I think we'd be in the same order of magnitude. Edit: actually I might be an order of magnitude off, depending on the length of life. If cows live a year before slaughter, vs bison living 10 years. No idea what the real numbers are.