After much consternation, vexation, investigation and search, I found it re-printed in a Malaysian newspaper from 1983. This just very recently (as in, today) popped up in a Google News search. And now having found the story, and being unsure as to how long it will remain visible this time; I am, for the purpose of preservation and scholarly critique under Fair Use in accordance with Title 17 of the US Code, going to reproduce it here in its entirety. I do not recall the original title, so I'm going with, "The Mouse-Cat".
After the unsuccessful colonial revolt, the British colonies in the New World were organized into the United States of Canada. In time, this vast and peaceful nation grew to include the entire North American continent. One of its most famous heroes was the Cisco Kid of the Royal Canadian Mounted Police.
Strange reports were coming in from prospectors in the Yukon. A new animal had been seen, a swift, elusive beast that the miners called a mouse-cat.
What made the reports so remarkable was the news that the mouse-cat, unique among mammals, had three ears. The Cisco Kid was sent to investigate.
The Cisco Kid returned from the Yukon empty-handed. The mouse-cat had proved too shy and clever to be captured. He had, however, observed the little animals closely, and he could vouch for the fact that they had not three ears, but four!
The controversy was referred to the Science Court, and in short order they handed down a verdict in favor of bilateral symmetry. "For," said the Chief Justice, "who are we to believe, the three mouse-cat ears or the count of Mountie Cisco?"[*]
It is possible that I introduced some spelling errors or inaccuracies. It's also possible that the Malaysian newspaper did so. They certainly didn't feel the need to attribute this work. Feel free to leave scholarly preservationist comments below, as scholarly preservationists are wont to do. And seriously, if you know where this story first appeared... or better yet,
[*] If you didn't recognize this as The Three Musketeers or The Count of Monte Cristo, then you need to read more. Follow the links, the books are free.
[**] According to the "100 Great..." collection, “The Abraham Lincoln Murder Case,” “Freedom,” and “Mouse-Kitty” by Rick Norwood copyright © 1982 by TZ Publications, Inc. Originally published in Twilight Zone under the group title, “Three Timely Tales.”