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How Many True Bison Are Left?


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#1 Eclipse Now

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Posted 07 March 2011 - 07:12 PM

Just watched "America, the history of the USA" and it covered the Bison getting down to 89 true individuals. Then I read the wiki and it said something about there being 350,000 Bison but many of them are 'Beefalo' cross breeds.

Anyone know how many true Bison are left? How's that gene pool going?

(Reminds me of the Aussie Dingo problem we have here. Most true-blood dingos are now on Fraser island as the mainland population are all cross-breeds with mongrel strays and feral European dogs).

#2 Turtle

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Posted 07 March 2011 - 07:50 PM

not sure where-all there are "real" bison, but yellowstone park came to mind & they have been there for ...well, eons. here's an update through 1997 claiming 3,500 animals. :turtle: :read:

http://www.yellowsto...dlife/bison.htm

...In the early 1800's, an estimated 65 million bison roamed throughout the continent of North America. However, market hunting and poaching had a devastating effect on the bison population; and by 1890, fewer than 1,000 remained! Even with the establishment of Yellowstone National Park, protection and sanctuary for the bison did not occur until the U.S. Army arrived in 1886 to protect the park's resources.

Due to protection and manipulative management (transplanting bison to different parts of Yellowstone), there were approximately 1,500 bison in Yellowstone National Park by 1954. Beginning 1968, the manipulative management of Yellowstone bison was discontinued and the population was allowed to fluctuate based on environmental conditions (i.e. winter weather, food availability, etc). In the 1970's and 1980's, there were a series of cool, wet summers followed by mild winters. These conditions allowed for an abundance of grasses for the bison to feed on and a reduction in the winter mortality rate.

In addition, snowmobiling in the park has helped more bison survive winters since the groomed roads cut down on the amount of energy that a bison uses to travel when compared to traveling through deep snow. By the winter of 1996 to 1997, there were approximately 3,500 bison in Yellowstone National Park. ...



#3 CraigD

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Posted 08 March 2011 - 12:09 PM

Just watched "America, the history of the USA" and it covered the Bison getting down to 89 true individuals.

Do you mean the current History Chanel series America the story of US?

My guess is that this count must refer to a specific herd, counted and documented in 19th century. Free-roaming American bison then and now were split into several separate herds, the finding and counting of which was and still is difficult, so I doubt an exact, exhaustive count could or can be made.

The number is mostly, I think, evocative of a dramatic scene – a wild herd once number a million or more, hunted over the course of a few decades (roughly 1850 to 1880) until eventually it could be encircled and counted, the count coming to exactly 89.

Then I read the wiki and it said something about there being 350,000 Bison but many of them are 'Beefalo' cross breeds.

Anyone know how many true Bison are left?

The American bison wikipedia article point to what looks to me like a pretty good answers:
500,000 in captivity on about 4,000 ranches (obviously making for some pretty small “herds”!), which aren’t counted for conservation purposes, and are believed to be widely “polluted” by domestic cattle (bos tarus).

30,000 individual “pure” (bison bison) bison, 20,000 of them adult, 15,000 of them wild (free-roaming).

Some genetic analysis leads zoologists to estimate that the true number of pure bison is 12,000 to 15,000.


How's that gene pool going?

This is a more difficult question, as distinct genes aren’t as easy to count as animals. However, I’m pretty confident guessing that the bison gene pool is OK.

I think we need to be careful to avoid too closely equating the metaphor “gene pollution”, referring to cross-breeding bison and cattle, with environment pollution, which can result in the extinction of entire groups of species. Catallo/beefalo still have bison and cattle genes, so doesn’t threaten to extinguish either of its parent species. Were these animals released into the wild, they and their descendents would presumably be re-absorbed into wild bison populations, as the traits their cattle genes give them – docility, extra-tasty meat, etc – don’t have high survival value in a human-free wild. The resulting animals might be chocked full or cattle gene “pollution”, but they’d look and behave like buffalo.

In an evolutionary sense, “American bison” is the result of the bovine family and the recent (last 20 million years) North American environment, just as the various other bovines in Eurasia, Africa, and elsewhere in the world are the result of the bovine family and those recent environments. Though I don’t think it’ll happen (a mere wild guess on my part), were humans to dissapear from the ecological scene in North America, I imagine something pretty close to the old America bison would reclaim its ecological niche.

The little I read about the history of bison conservation (for background before posting in this thread) was inspiring. American bison could have become extinct ca. 1900, but a handful of thoughtful people (the standout example being James "Scotty" Philip) intentionally kept and grew herds of captured wild bison.

I’m not sure if the popular accolades of these people as “men who saved the buffalo” are scientifically factual – some herds, such as those at Yellowstone, may have survived without intervention – but even if that’s the case, I admire them for their forward-thinking and effort.