Descenting is a surgical procedure to remove the anal sacs, which are musk-producing glands on either side of the anal opening.
Descenting alone does nothing to change ferret body odor. The musk secretion has a very pungent odor of its own, but is secreted only when the ferret is startled and frightened.
All carnivores have anal sacs that produce a strong smelling secretion with a distinctive odor for each species. The anal gland secretion of mustelids, particularly skunks, is more pungent than that of other carnivores. The contents of the sacs are released as a defense against attackers, most effectively by skunks.
Properly handled pet ferrets rarely discharge the contents of their anal sacs, because they never feel sufficiently threatened. This defense is most likely to be triggered when the ferret is physically attacked by another ferret or a larger animal. (See 'Fear Reaction' in Do Ferrets Bite?) Although the odor of ferret glands is very strong, it dissipates completely in a short time. Descenting is not absolutely necessary for a ferret to be a good house pet. Some ferrets appear to have 'loose' anal sac openings, and they leak a little of the secretion all the time. The unpleasant odor is unacceptable to most pet owners, and these ferrets need to be descented. Pet shop ferrets are usually descented when they are spayed or neutered, before they leave the breeding farm.
It is best to descent ferrets when they are only 6 to 8 weeks old. The surgery becomes more difficult and more traumatic as the ferret gets older and fatter. Descenting incisions in young animals are not stitched and heal completely in several days.
Occasionally young kits have a prolapsed rectum, indicated by protrusion of bright pink tissue from the anal opening. Some have attributed this condition to the descenting surgery, but that would be an very uncommon cause. Rectal prolapses also occur in kits that have not had the surgery. Rectal prolapse may be due to the weaning process, when kits suddenly eat only dry food without the laxative effect of milk. Firmer, drier stool causes mild straining that may induce a temporary rectal prolapse, which usually disappears without treatment. Proliferative colitis can also cause rectal prolapse.