The "extra tooth problem" is universal in carnivores; indeed, in all
mammals--its just not often noticed.  In most mammals, the deciduous (baby)
teeth remain for immediate use until the permanent teeth have grown in
place.  This is not just for the canines, but for the incisors, premolars
and molars as well.  In humans the process can take several weeks, with
noticable toothy grins during the eruption of the permanent tooth.  But
carnivores need their teeth to survive, so the baby teeth remain as long as
possible, while the permanent teeth grow under, beside, or behind the baby
teeph.  As the permanent teeth grow (from the crown down) the deciduous
teeth disolve (from the root tip up).  About the time there is enough root
to stabilize the permanent tooth, the baby tooth has lost enough root to
become unstable.  In most cases, the process is well timed, with one
dropping out just as the other is nearly fully erupted, but sometimes the
timing is off, and one comes in or drops out early.  Usually, the tooth
comes loose while eating, and is swallowed.  The entire process can appear
to be very rapid, and unless you look carefully, you would never see the
process going on at all.
 
Teeth are very hard and last well in the fossil record, so there are
thousands of articles concerning aging animals by their teeth.  Within a
species, tooth eruption is fairly predictable, and the age of the animal can
be (usually) predicted to within a week or so.  Nutrition, calcium intake,
disease, and environment can shorten or lengthen the time scale, but
generally, 8 to 9 weeks is about right for the replacement of the lower
canines.  (I must point out that breeds of ferrets with shorter faces tend
to have more dental problems than those with longer faces.  I know nothing
about judging, or what is "preferred," but those who wish to develop such
varieties should study the problems that plague short-faced dog and cat
breeds.  These animals may or may not follow the tooth replacement timetable
most other ferrets follow.  This comment is not referring to the normal
shorter face of the ferret when compared to the polecat, but to "pugs.")
 
There is the occassional ferret that has extra, or supernumerary teeth.
This most often occurs in the front teeth (incisors) and is almost always
harmless. Nothing needs to be done unless the extra tooth physically
effects the position or use of another tooth. If you suspect such
problems, let a vet open the hood and take a look-see. Pulling the tooth
cures the problem.
 
BTW, the ferret only has 4 molars; one on each side, top and bottom.  It is
way in the back, and is very small.  (In cats, its even smaller) The big,
sharply pointed tooth is a premolar specially adapted for cutting or
shearing meat and bone.  Technically, when you watch a ferret eat dry
pelleted food, it is not chewing as much as it is cutting the pellet into
small enough chunks to swallow.  Often, you will see the little guys twist
their heads sideways while eating, or eat things out of the side of their
mouth, which helps get the food onto that cutting tooth (I really notice
this when they are eating sticky foods.  Bear will actually roll over trying
to get the sticky raisin onto the tooth for cutting).  Poole reported
noticing ferrets fed dry pellets had alot more wear on this tooth than those
fed wet or natural diets, and could distingish feral fitch from captive
domesticates based on this criteria.
 
Bob and the Toothy 13
[Posted in FML issue 1467]