Pleistocene and beginning Holocene, we can assume that a deterioration of the area in terms of its animal-carrying capacity was in the process, which was not favorable for the mammoth populations.
At the same time, mammoths in the Colby site area which were facing problems due to diminishing forage were faced also with an intrusion of obviously successful human predators who were killing mostly young animals. For a species in which females produced young at the age of about 15 years, had a gestation period of under 2 years, and a mean calving interval of somewhere around 6 years (see Laws et al. 1975), the combination of human predation and a deteriorating environment were operating against survival of the species. Consequently, both human predation and climatic factors could have had strong implications in mammoth extinction on the Northwestern Plains.
On the other hand, deterioration of the environment was toward present conditions, which were continually more favorable for horse habitat, as can be demonstrated today by ever-increasing herds of feral horses. The archaeological record has produced little if any reliable evidence that either the Pleistocene horse or camel was systematically hunted by Clovis (see Frison et al. 1978) or any other cultural group, and both species became extinct in the area. However, the bison, which was the most heavily hunted of all the species by human predators, did manage to escape extinction along with the pronghorn, which was the next most heavily hunted species. .. We are left with the conclusion that more data are needed before the Pleistocene extinction problem can be resolved.
I might add that the African lion-sized Smilodon and the Short-faced bear, "the most powerful predator of the American Pleistocene," [think Grizzly bigger than a Clydesdale here] also became extinct about that time, and no one I've read has ever suggested that they were hunted to extinction. On the contrary, someone (who? Hmm. I can't remember.) has suggested that humans couldn't occupy the western hemisphere until the Short-faced bear became extinct.
These 'hunted to extinction' arguments certainly resonate with our modern environmental consciousness and are often the lede in news reports on any archaeological excavations that feature the remains of Pleistocene megafauna. This gives the whole argument a certain ad hoc flavor of sensation-seeking that may sometimes be deserved.
In a broader sense the 'hunted to extinction' argument is ad hoc, as climate change alone can easily explain the late Pleistocene extinctions. Either that, or there remains undiscovered the clan that hunted the Smilodon and Short-faced bear. As by some lights these folks must have existed, I think I'll jump on the naming priority by calling them the Ferrous Huevos Culture.
"Wind. Sun. Hydrogen. They are odorless, tasteless, invisible and abundant. And they can be harnessed to generate electricity, power cars and heat homes. So, hey, let's stop dallying! Replace those shameful fossil fuels with clean renewables. What is taking so long?" Says James K. Glassman, via Reason Express.
Glassman goes on to point out: "But there is a reason that renewables, despite a history of generous government subsidies stretching back to 1982, haven't made a dent in the dominance of oil, gas and coal - which together account for 85 percent of the energy used in this country. The reason is cost. As energy sources, wind, sun and hydrogen are hugely expensive and inefficient. Fossil fuels aren't.
The renewables have their own environmental costs as well. Wind turbines sparkling in the sun as far as the eye can see isn't my favorite vision of the future of southern Wyoming, but it's fast becoming a reality in some areas. They may be clean, but they're mighty unsightly. So are all the shiny power lines strung across miles of the Big Empty.
One area where renewables do have promise is in new rural development. The REA expansion of electric lines to rural customers was hugely subsidized and these subsidies are now largely ended. The cost for new rural power line