Female ferrets go into heat in their first spring and they will remain in season until successfully mated. If mating does not occur, the females will succumb to aplastic anemia and die a most painful death.
The domestic ferret is known to be affected by several distinct ferret health problems. Among the most common are cancers affecting the adrenal glands, pancreas, and lymphatic system. Viral diseases include canine distemper and influenza. Certain health problems have also been linked to ferrets being neutered before sexual maturity was reached. Certain colors of ferret may also carry a genetic defect known as Waardenburg syndrome. Similar to domestic cats, ferrets may also be affected by hairballs or dental problems.
Like many other carnivores, ferrets have scent glands near their anuses, the secretions from which are used in scent marking. Ferrets recognize other individuals from these anal gland secretions, as well as the sex of unfamiliar individuals. Ferrets may also use urine marking for sex and individual recognition.
Males, if not neutered, are extremely musky. It is considered preferable to delay neutering until sexual maturity has been reached, at approximately six to eight months old, after the full descent of the testicles. Neutering the male will reduce the smell to almost nothing. The same applies to females, but spaying them is also important for their health. Unless they are going to be used for breeding purposes, female ferrets will go into extended heat. A female that does not mate can die of aplastic anemia without medical intervention. It is possible to use a vasectomized male to take a female out of the heat.