Perhaps not in New York City or San Francisco -- but there are THOUSANDS of "dead bears" registered annually by hunters, and bones of bears are found in caves, sink holes, after forest fires and as road kill.
With most of America covered by hunters, fishermen, hikers, climbers, trail bikes, ATVs and whatever -- not ONE one has ever come out of the boondocks with ANY physical evidence or photograph that was credible to scientists".
The writer of the article you quoted - could have answered his own question about the absence of Bison bones on the plains with just a little research..
http://www.kshs.org/research/topics/business/essay.htm
Collecting bones was a BIG business in the 1800s....
"Another industry sprang from the slaughter of buffalo. Bone pickers were paid $4 to $6 a ton for the dried buffalo bones. Shipped east, the bones were then ground and used in the manufacture of fertilizer, combs, dice, buttons, and bone china dishes. Some homesteaders used this business to supplement their farm income."
I agree with you, big game hunters would have found tracks if this thing did exist. Period. End of Story.
"Another industry sprang from the slaughter of buffalo. Bone pickers were paid $4 to $6 a ton for the dried buffalo bones. Shipped east, the bones were then ground and used in the manufacture of fertilizer, combs, dice, buttons, and bone china dishes. Some homesteaders used this business to supplement their farm income."
You missed the point, the late Dr. said animals "not killed by man." All of those Bison bones you are speaking of were from animals killed by man in a short period of time during the great slaughter of the Buffalo in the 1870s. He was speaking of the millions of bones that should have been there collecting on the plains during the last 40,000 years but weren't.