Letting your female go into heat is dangerous for her. Unlike humans and many other animals who produce eggs according to a biological clock, ferrets are "induced ovulators": When a female ferret goes into heat, her body is waiting to be bred by a male before it will produce eggs to be fertilized. When she is "bred" (either by a real whole male, by a vasectomized male, or artificially with injections of hormones), her body will produce eggs and she will either get pregnant or have a false pregnancy—all the symptoms but no kits. Ferrets do not come out of heat on their own; they stay in heat u