I have a friend who claims that female ferrets will die if they don’t breed. Is this true? Are there any others?
That’s what my vet told me when I had a female ferret. IIRC, in that family–including weasels, skunks, mink, etc.–the female will remain in estrus until she breeds, or bleeds to death. (Wiki says the cause of death will be aplastic anemia.) I’m sure a more knowledgeable person will be along shortly to confirm or debunk this, and hopefully to supply more detail.
Every animal will die, whether they breed or not.
I was told the same thing by my vet in my ferret owning days. She also said that this was why ferrets sold in the US are spayed as very very young ferretlings (“kits”, actually) - so there’s no danger of a non-expert ending up with a female dying because they put off the spaying too long. When they spay them, they tattoo a little dot on their ear to signify the surgery’s been done. Another little dot shows that they’ve removed the scent glands. So the next time you’re in the pet store, check out the ferret tatts!
She also said that if your female does go into estrus, you can mate her with a sterile male and that will trigger the end of the estrus, and then you can go in and spay her, but it’s hard to find males for this service at short notice, and that not all neutered males are even interested in servicing females.
I asked if she had any ferret dildos, but she just laughed and changed the subject. She didn’t say no, however!
Ferrets (and other animals) are induced ovulators, which means they do not ovulate until they are bred. Once an intact female ferret starts cycling (they are seasonal polyestrus), it will remain in heat (ready to be bred) until it is bred (and then ovulates), contrary to other domestic animals (dogs, cows, horses, cats) that have a period when they are not in heat.
The major hormone during that part of the cycle is estrogen. The increased levels of estrogen cause bone marrow supression, leading to pancytopenia (among them aplastic anemia, no red blood cells are formed).
Most ferrets in the pet trade, though, are sold already spayed.
WhyNot, they can also use injectable hormones to induce ovulation.
:rolleyes:
Oh, cool!
For the owner, I mean. Probably a raw deal for the ferret, unless you buy her dinner and drinks first. 
Heh… I’m sure the ferret will welcome the injection to stop her body from killing itself. She may appreciate the breeding more, but oh well…
Vulcans
I know it’s not the question, but there are tons of plants that will die if they’re allowed to flower (in other words, breed.) For example, you shouldn’t let your Venus flytrap send up a stalk, because it probably won’t live through it.
Moties
actually I was sure it was the aliens in “Mote in God’s Eye”, but neither of us had it right for th OP. 
In US no intact pet ferrets are allowed to be purchased without a breeder’s license. Male ferrets are not exempt despite a lack of health concerns. The reason my ferret book give for the practice, however, is that there’s a worry of ferrets getting loose, building up significant populations, and out-competing native species. If it’s true about the females, though, it seems like a pretty groundless worry considering how infrequently ferrets escape to the wild; it sounds like they’d probably die before meeting up with a male escapee.
Decapodians (Zoidberg’s species)
I thought they died if they did breed
Oops, that’s right.
Ironically enough, Shakers.
Are you certain? We had, at one point, been planning to purchase a male from a breeder, and not have it neutered until it was a year old (since early neutering leads to some serious health issues). That was our vet’s advice. Are you saying that would have been illegal, or would we have needed to signed some waiver with the breeder promising to get the ferret neutered, etc.?
Here’s MA’s policy on it, and considering it’s supposed to be a federal law, I assume the same holds true in your state as well.
A quick look on google for “‘breeder license’ ferret” gives the same info on gov pages for CA, NH, OK, IN, VT, MI, KS etc.