According to Merck Veterinary Manual, both male and female ferrets reach sexual maturity at around four to six month in age. Like a human applying perfume or cologne before a night at the club, when the time comes, both male and female ferrets (but more so males, according to Friendly Ferret) emit a pungent smell to attract a mate. Though overall ferrets are difficult to breed, once in heat both male and female ferrets will remain in heat until they've found a mate (via West Davis Vet Clinic).
This means that female ferrets remain in estrus until they mate, according to Today I Found Out. Also notable, the simple act of mating with a male ferret, sometimes called a hob or hobbet, usually is not enough (per another post at Friendly Ferret). Once the female has mated, if she is not impregnated, she will go into heat again.
As The Countryman's Weekly goes on to explain, like other mammals, when a female ferret enters heat her body produces a hormone called estrogen, which spurs ovulation. If no mating occurs, then her body continues to pump out estrogen, causing progressive depression of bone marrow and finally a condition called pancytopenia, caused by aplastic anemia, according to West Davis Vet Clinic. If that happens, your jill ferret's blood will have decreased levels of white and red blood cells and platelets, and after too long, that will kill her. Luckily, though, there are other ways besides impregnation to save her life.
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