I happened to be surfing YouTube the other day and I came across some interesting home videos of a ferret as a pet, and of the tiny stoat who lives off attacking & killing the much larger rabbit. That let to finding more and more related links to other similar animals -- all relatively small, scurrying, furry, cute but kinda nasty busybodies. I see some difference in size, agility, color, etc -- but are they all related?
Luckily I discovered someone else wrote a whole book on the problem... "This Is Not a Weasel" by Philip Mortenson
It's on my reading wish list