>I've read on the FHL that you know a lot about ferret skeletons and teeth.
>Maybe you can settle a bet between me and my roommate... I say ferrets
>don't have molars and she says they do....It's for a bottle Wild Turkey...
 
Since I'm a beer man and dislike the hard stuff, there is no danger my
answer can be influenced by some sort of alcoholic payback.  But you can
tell your roommate that she owes me an ice-cold beer.  You lose.
 
Ferrets indeed have molars, although as a percentage of the overall dental
arcade, they are minimal.  While there are differences between males and
females due to sexual dimorphism, the dental arcade is about an inch long,
from front to back.  Of that entire distance, roughly about 7/8ths is
composed of puncturing or cutting teeth, and about 1/8th is crushing teeth.
In terms of percentages, the only other mammalian carnivore with a lower
percentage of cutting teeth to molars are cats, where some species have
completely lost their molars.  The reason ferrets, or rather the polecat
progenitor, has maintained crushing teeth despite their obligate, primary
carnivore status is because they consume hard-bodied insects and
crustaceans, and the molars were retained to crush the exoskeletons.  Also,
polecats eat a lot of tiny rodents, and the molars help to break the bones
prior to swallowing.  These are not the type of molars typically used to
grind vegetation to a pulp.
 
In the upper, or maxillary arcade, on each side there are two tiny molars
in the back, behind the cutting teeth.  If you look in your ferret's mouth
when they are yawning, the first molar is the one which looks like it was
twisted sideways.  That molar is about 1/8 by 1/4 of an inch, and it has
two tiny cones at either end, the function of which I'll explain later.
Behind that tooth is a very tiny little molar, about 1/16th by 1/8th of an
inch.  This is a weird tooth, but is typical of mustelids (and one of the
easiest ways to identify their remains).  One explanation for the tooth
size and shape is that it was a molar originally being lost, but during the
evolutionary simplification of the dental arcade, the remnant part started
to serve a function, so just the reduced portion was retained.  You can
see why when you look at the mandibular arcade.
 
There is only a single molar on each side in the lower, or mandibular
arcade; a round cone-topped tooth that is only about 1/8th inch in diameter
if it is lucky.  This tooth butts against the last premolar, which sort of
has a mountain-like profile with a tall peak, followed by a short peak,
then a sort of flat area in the back supporting a tiny cone.  This tooth
is called the carnassial, or cutting tooth (in some older texts it is
called the sectorial tooth).  This is the tooth which the ferret uses to
cut food apart; either dry extruded foods or fresh bone and muscle.  If you
carefully place the upper and lower arcade together, you will see the upper
molar partially strikes the flat area on the back of the lower carnassial,
with the remaining half hitting the front of the small round molar.  The
tiny 2nd upper molar hits the back of the lower 1st molar.  This creates a
sort of interlocking action similar to what you would see in the jaws of
vise grips.
 
Biomechanically, this is absolute proof the molars are used to crush bones
and exoskeletons rather than to pulp plant material.  How?  Have you ever
cut glass or cracked hard nuts?  If you use an anvil with two points, and
strike the unsupported area with a pointed hammer, the material easily
fractures in a controlled way.  That's why the ferret molars (and
carnassial) have the cones on top of the flattened areas, and why parts of
teeth (with the gaps between them) are used rather than a single upper and
lower tooth.  The construction of these teeth create a powerful nutcracking
action which can break off segments short enough to be easily swallowed.
Pure genus!
 
Pet ferrets use their "jawcrackers' to break dry kibble or extruded foods,
and that's the number one problem I've seen in the teeth of pets.  The
kibble is very hard, but not arguably harder than bone or some parts of
insect or crustacean exoskeletons.  Ferrets will place the dry food on
the carnassial, and use the cutting edge and flat area to cut or crush the
food into swallowable size.  In a natural diet, this hard work only occurs
as a tiny percentage of chewing time, and much of the time the teeth are
cushioned from the hard parts with meat or other tissue.  Under these
circumstances, the back teeth can last the lifespan of the animal.  But
when eating dry foods, such as kibbled or extruded foods, the hard stuff
is not cushioned by tissue, and tooth damage (wear) is continuous.  This
causes a tooth wear rate from 2 to 5 times faster than in ferrets eating
a natural diet.
 
In a practical sense, the wear rate in the back of the mouth is much higher
than the front, which makes sense considering where the work is being
done, so a quick inspection of the dental arcade doesn't necessarily show
tremendous wear.  However, in the back where the heavy work is done, the
upper 1st molar (the one that looks like it was twisted sideways) is
often so worn down that it has fractured into two pieces.  The tiny upper
and lower molars are often ground down to their roots.  On the lower
carnassial, the rear flat area is so worn that it is at or below the
gumline, and the cutting edge is clearly blunted and flattened.  As I said,
this is hard to see in living ferrets; you have to open the mouth nearly as
wide as it will go and peer into the back to see what I am talking about.
There is ALWAYS reactive bone tissue present at the gumline, which
indicates chronic inflammation, probably due to low grade gum disease.
This dental wear is exclusively a byproduct of eating hard, dry food and
is NOT found in wild polecats, feral ferrets, or pet/working ferrets fed
a natural diet.
 
I'll post some photos which will clearly illustrate these problems in a
week or so, as soon as I can finished the basement and get the paper off
for review (the paper is about introduced Post-Columbian epizootics and
wildlife populations).  You will be as shocked as I was when you see the
differences in the wear rates of the teeth, as well as in the diseased
state of the bone supporting the teeth.
 
As for solutions, the best solution is for the pet food maker to modify the
food so it isn't as hard, but that is unlikely to happen.  Simply put, dry
food has little odor, can be stored almost anywhere, and doesn't spoil in
the dish.  It keeps the teeth somewhat clean because it wears them down,
although not as good as often suggested.  People like that, and they buy
such foods in vast quantities.  Softer food would either require some sort
of preservative, or would have to be treated to special storage conditions,
which people don't like.  So even if pet food manufacturers wanted to
create a food better on the ferret's teeth, it is unlikely they could get
enough people buying it to make it economically possible.  All I can
suggest is that you buy dry food in small quantities and store it in a
humidity controlled area, such as a refrigerator.  You can add some broth
to the food prior to feeding to soften the material, with maybe some dry
stuff sprinkled on the top to add in cleaning the teeth.  Other than that,
have yearly checkups of your ferret's teeth (or more if your ferret has
problems), have them professionally cleaned, and perhaps consider brushing
their teeth at least a few times a week.  If you do that, then you can add
some softer foods to the diet, such as the canned ferret foods I've seen in
a few markets.
 
Bob C
[Posted in FML issue 3410]