Here are some questions for our biologists and other experts out there.
 
If unaltered female ferrets are not bred when they come in heat, they
usually become sick and die.  This seems to be a very foolish way to
reproduce.
 
Is this trait shared by any mustelid cousins?  Or any other animals?  How
did such a thing come about?
 
Did early ferret domesticators purposefully or accidentally breed for such
behavior?  Or was it a chance mutation that by the vagaries of genetics and
distribution became prevalent?
 
What sort of social behaviors could this biological behavior lead to?  We
know that black footed ferrets live in colonies, but given the aggression of
male domestic ferrets in rut, this seems disharmonious.  Perhaps domestic
ferret ancestors lived in harems, with one male servicing many females.  But
that would lead to disastrous results if the male was lost without a
replacement.  Now one female having a harem of males... that sounds fun, but
then there's that disharmonious thing again.  European polecats are solitary
animals, according to a nature program I saw on tv once, but that doesn't
sound good for precursors of our domestic ferret: if a female can't find a
male come mating time, curtains for her.
 
Maybe they formed stable pair bonds, with one male and female remaining
together for several years, like geese.  That would explain why so often
they become despondent at the loss of a playmate.
 
I invite comments and speculation on these ideas. Note: although I have a
scientific background, I am not a biologist, reproductive or behavioral!
 
Linda, Richard, Joy, Belle and Caruso
[Posted in FML issue 1563]