Apparently they can interbreed with domestic cattle, and most of the one's called "bison" are mixes. And we got them down to 1,091!Flumper wrote: ↑Mon Apr 29, 2019 4:36 pmI googled: how many bison are left in united statesFSchmertz wrote: ↑Mon Apr 29, 2019 4:31 pmThere's only that many because we eventually made efforts to prevent their extinction.
Also:
https://en.wikipedia.org/wiki/Bison#DescriptionGenetically pure B. b. bison currently number only ~20,000, separated into fragmented herds—all of which require active conservation measures.
So I don't get where your getting "half million or so" from.
and got: An estimated 20 to 30 million bison once dominated the North American landscape from the Appalachians to the Rockies, from the Gulf Coast to Alaska. Habitat loss and unregulated shooting reduced the population to just 1,091 by 1889. Today, approximately 500,000 bison live across North America.
I know "north america" is more than just the U.S., but I'm not sure how many bison are in canada and mexico.
Hell, I think that Ted Turner has over 50,000 bison on his ranch. Now, the term "genetically pure" might be an issue....
I'm sure that got them close to insufficient genetic diversity for survival.