Most carnivores, including the ferret, make a point of eating bone,
especially parts of the skull and pelvis, the ribs, and the ends of
the long bones--exactly where red bone marrow is found.  Red bone
marrow is rich in minerals, easily absorbed irons, proteins, fats, and
fat-soluble vitamins, and is nearly a perfect food for carnivores.  I
have seen uncounted thousands of carnivore-chewed bones, and they all
have identical characteristics, regardless if my ferret chewed them
yesterday, a dire wolf chewed them some 15,000 years ago, or early
mammals chewed them millions of years ago.  The species may change,
but the biomechanics of bone and bone eating are exactly the same.
 
In terms of bone-eating biomechanics, bone can be grouped into three
basic categories--that which is easy to eat, that which is hard to eat,
and that which cannot be eaten.  Easy-to-eat bones are those that can be
effortlessly cut into pieces or crushed for swallowing, allowing stomach
acids to do their magic work.  Hard-to-eat bones are those that a ferret
may be able to consume, but eating them requires considerable expenditure
of time and effort.  Those bones (or parts of bones) too hard to eat
might be cached, they might even be gnawed, but they are not consumed
unless small enough to swallow whole.  Not surprisingly, the bones that
are easy to eat are composed mostly of trabecular bone, usually covered
with a thin layer of compacta.  More importantly, mimicking honeycombs
filled with sweet honey, the trabecular spaces are filled with
high-protein, high-fat, high-micronutrient marrow.  When a carnivore
chews this type of bone, the bone doesn't break into small fragments
having sharp edges and pointy ends.  It breaks into small, irregularly
shaped masses of marrow-filled spongy bone.  These bone fragments are
no more dangerous for a ferret to eat than dry, extruded food, and
nutritionally, far better.  Most do not survive the digestive process --
at least in recognizable form.
 
Hard-to-eat bone is generally composed of layers of compacta, and can
be quite hard.  I have compact bone fragments that once supported the
weight of dinosaurs, some 65 million years ago.  I have chunks of 20,000
year-old mastodon compact bone that look as if the animal died just a
few years ago.  Compact bone is a bioceramic, a sort of "bone china."
Consequently, it shatters like glass, and can be broken into fragments
having sharp edges and points (the bone knives I mentioned earlier where
made from compact bone).  Compacta makes up the shafts of long bones, and
is ultimately the reason why some people are afraid of ferrets eating
bone.  What few people understand is that these bones are HARD to
eat -- few carnivores actually try, less those with special adaptations
like hyenas, or those that are starving or living in marginal
environments.  Most carnivores will gnaw bits of the diaphysis away
until the task becomes too difficult, and then they will abandon the
bone for something better.
 
There are some skeletal parts so hard that carnivores rarely attempt to
eat them.  If small, they may be swallowed whole, but little attempt is
made to break or gnaw them.  This bone includes the hardest portions of
the long bone shafts, the teeth, and portions of the skull, especially
the petrous portion of the temporal bone (the petrosal -- arguably the
hardest part of the body).  Not many carnivores are willing to attempt
to eat this type of bone, not even hyenas, but it doesn't matter much
because they contain few nutrients.
 
Regardless of species, most carnivores eat off the ends of the long bones
and leave the hard, potentially dangerous shafts behind; the exception
are some hyenas species, whose massive teeth and jaws can eat nearly any
bone from any animal.  Polecats, feral ferrets, and pet ferrets only
rarely eat the entire bone shaft, but will make exceptions if starving,
living in a marginal environment, are "bone starved" (has a unsatisfied
desire to chew), or the bone itself is soft (immature chickens, boiled
bone, etc.).  What this means is ferrets, like most carnivores, chew off
the soft trabecular bone preferentially over the harder compact bone.
Soft or hard, what is the ACTUAL impact of bone gnawing on the teeth?
 
Bob C
[Posted in FML issue 4158]