Of course do I have a snappy retort for your question, dear @redpanda: is foz an "undiscovered species"?
The Pacific Northwest is a bit more than just the Rockies:
[ame=http://en.wikipedia.org/wiki/Pacific_Northwest]Pacific Northwest - Wikipedia, the free encyclopedia[/ame]
Indeed, there are various reports of wild hominids all over North America, including Florida (the Skunk Ape), with widespread reports of sightings in particular in the Northwest.
File:Bigfoot Sightings in USA.png - Wikipedia, the free encyclopedia
Human activity does not rule out the often unnoticed presence of larger wildlife. A nice example of this was illustrated by a picture sign next to the cougar exhibit at Denver Zoo: it showed a lady holding a toddler, with a canyon in the background. On closer observation, one could observe the head of a wild cougar in the bushes just behind the lady. Both she and her photographing husband only noticed the cat while sitting happily back at home and going through the holiday photo collection.
This should by no means serve as an argument to support the idea of large unknown wild primates roaming America, but maybe make you, dear reader, a bit more careful before making all too hasty assumptions. Sometimes, areas that are thought to be well-known and of little significance for zoology, might sport something unusual & significant-as various "cryptozoological" discoveries exemplify again and again.
Given the little percentage of (prehistoric) biomass actually making it to be found as recognizable fossils, one should be careful to base one's argumentation on their nonexistence. Before the discovery of their fossils, people would have doubted the existence of bizarre creatures such as Stomatosuchus, Thalassocnus sp. or Hurdia victoria. So not having found any ape fossils in North America yet just means that-that no ape fossils have been found in North America - yet. However, it doesn't rule out their finding in the future, although I personally doubt it.
Honestly, I'm neither really convinced of nor really interested in the existence of large unknown primates in North America or the Himalaya.
What I consider interesting is that the phrase "believe" always pops up in these discussions. As if dealing with the "crypto superstars" was a decision of faith!
Such an attitude makes it hard for sceptics and fans alike to notice & acknowledge the most important part of the word cryptoZOOLOGY as it was meant by Heuvelmans-as a zoological approach, but not as an escapist playground for self-acclaimed "monster hunters".
Therefore Bigfoot, Nessie and Yeti would have to qualify for the same rules of scientific identification all other species have and had to endure. However, this would also mean to have at least one real complete specimen available for the profound systemic examination by qualified specialists, with the results available to the public. As long as this criterium can not be matched, I see no reason to "believe" in the existence of Sasquatch, Yeti etc. as something other than a wild mix of misinterpretations of already known animals, local folklore, dupery and sensationalism.