You'd be surprised at
the variety of sounds a bear can produce (black bears, in that website's case). You can also hear more variations on bear noises (but not apelike ones) in
these videos. With that in mind, it wouldn't surprise me at all if a bear could produce a "simian" sounding noise.
But, hey, maybe it wasn't a bear making the noise. Perhaps it was a deer or an elk making the noise while a bear made the track/tore up the forest/scared the animals. As several of the elk sound recordings
here show, elk can make some rather apelike noises. You can hear more elk noises
here.
I've heard that a deer screaming sounds rather eerie as well. In addition to the sounds given there, I have found
another website with several deer sound effects.
This video starts with what's supposedly the sound of a Bigfoot roaring (the comments claim it was lifted from "The Legend of Boggy Creek") and one of the commenters (panikdapig) notes that the beginning of the roar sounds like that of a European Red Deer.
This site says that "It is impossible to accurately describe the range of sounds that a male red deer can make--the animal can sound like a howling wolf, screaming howler monkey or even a fog horn. " According to an article cited on the
Wikipedia entry on the subject, "Male European Red Deer have a distinctive "roar" during the rut, which is an adaptation to forested environments, as opposed to male Wapiti (or American Elk) which "bugle" during the rut in adaptation to open environments. The male deer roars to keep his harem of females together. The females are initially attracted to those males that both roar most often and have the loudest roar call. Males also use the roar call when competing with other males for females during the rut, and along with other forms of posturing and antler fights, is a method used by the males to establish dominance. Roaring is most common during the early dawn and late evening, which is also when the crepuscular deer are most active in general." But as
this video shows, European Red Deer are more than fine with roaring during the day. The entry also notes that elk and red deer are closely related.
I should also note that
it appears that some European Red Deer are kept in ranches in parts of the USA.
Here is a video of a red stag roaring in a way that would sound quite similar to the "Bigfoot roar" if its voice was deeper and it did certain noises in a different order.
Waitwaitwait...you've never heard of the "Leprechaun in Mobile, Alabama?" You'd better watch
this (you can see the "leprechaun" shape in the bark at around 2:42 into the video).