Such as when it leads this kind-hearted Craigslist user in Richmond, Virginia to refer to a ferret as a “cat snake” (h/t Paul):
If you can’t see the screenshot, and the Craigslist post gets removed, here’s what it says:
Found! Cat Snake? (Richmond)
Found (assuming) pet. Some sort of cat snake? Long and nimble but with dryish fur and cat teeth. Seems to like cat food, but isn’t a cat. Please come take this off my hands it smells weird.
I hope the cat snake finds its way home.
(To be fair, ferrets are also sometimes known as polecats, and the possible origin of that name just became clear to me.)
(Yes, I realize there’s an above-even chance that the Craigslist post is a joke. It doesn’t alter the likelihood that many, many people don’t know what a ferret actually is. I’ve spoken to people who think they are rodents. They’re actually much more closely related to cats, and would probably take offense at either comparison.)