"mountain boomer"

[jdespres at MERRIAM-WEBSTER.COM]

I didn't mean to dismiss any etymological hypotheses out of hand,
or to imply that animals couldn't possibly be named after attributes
they were once believed to have but actually don't.  My doubts
about the 1928 explanation "they make a peculiar noise, whence
the name" have more to do with the sparsity of linguistic evidence
than anything else.  I think it's certainly a good idea to put the
statement out there as a hypothesis (which is what DARE does),
and I think it has to be taken seriously, but I'm not sure it's a good
idea to write a definitive etymology based on one rather truncated
statement until one knows exactly what lay behind it (the
testimony of one person, or five, or a hundred?), and without
confirming that an unusual noise that might be construed as a
"boom" can actually be heard in the vicinity of the animal.  What if
the "peculiar noise" were nothing like a boom and the speakers
just assumed the animal was so named because it made a funny
noise?  Couldn't they be reinterpreting what the actual reason was
for the naming of the animal?

Sure, it's possible that "mountain boomer" began as a term for a
squirrel, that the term found its way to the west coast in that
sense, and that was ultimately transferred to a beaver-like rodent.
Why not?  I'd feel more confident about asserting that as a
probability, though, if I saw more linguistic evidence of the putative
migration, and if possible, some confirmation of the plausibility of
the semantic shift involved.  It seems to me that, until you can
prove definitively that that's exactly what happened, other
explanations can't be ruled out.

I should say that my employer treats these words in pretty much
the same way that the OED and DARE do -- it groups them all
under the same headword, which implies a common origin -- viz.,
"mountain" plus "boomer" in the primary sense "one that booms."
That is the default explanation, the one that, until something better
comes along, makes the most obvious sense.  I interpreted
Jesse's question as inviting a questioning (or confirmation) of this
default assumption, which was what prompted my remarks.
Without further investigation of the matter, though, I certainly don't
think they outweigh any other explanations on the probability scale.

Joanne