The polecat progenitor (ancestor) evolved dealing with bones of various
sizes, otherwise they would be extinct or short-legged cows.  Polecats
eat most animals smaller than themselves, and some much larger.  Those
prey species subsumed within the Vertebrata have, in fact, many small
bones.  I know of no way a carnivore can consume small prey animals
without eating many tiny or fragmented bones.  In fact, one of the ways
zoologists determine the diet of a carnivore is by identifying the teeth
and bones (and fur) found in the feces.  Yet, in more than a century of
scientific literature, I can find less than a half dozen instances where
the confirmed cause of death of ANY non-domesticated carnivore was from
eating bone.  Admittedly, there are many reports pertaining to dogs
having problems eating bone, but they are domesticated animals with
significant skull changes (more on this later).  Ferrets were primarily
domesticated as mousers and ratters, and for hunting hamsters, marmots,
and sousliks, a type of European ground squirrel.  Later, as cats
supplanted ratting, hamsters became rare, and rabbits were introduced
into greater Europe, ferrets were used for rabbiting.  Because of this,
as well as the frequent crossing of ferrets back to polecats to insure
stronger hunting drives lost through domestication, while behaviors has
changed greatly, and reproductive physiology to some degree, the shape
and size of the body and skeleton has not.
 
This quite simply means that if polecats possess the mechanical ability
to eat bone, so does ferrets.  This is supported by the presence of
feral ferrets in New Zealand, whose diet is composed mostly of rabbits,
rodents, lizards, birds, and carrion--all containing small bones.  As a
bit of additional evidence, consider the historic diet of ferrets, which
always included (at least in the better circumstances), part or complete
animal carcasses.  At one time (even now) these included culled chickens,
rats, mice, snakes, fish and eels, making it hard for the ferret NOT to
encounter bone on occasion.  There are NO historical documents, at least
that I can find, that suggest ferrets have ever had a problem eating
bone.  Indeed, MOST of the ferret books from the last century suggest
whole carcasses, containing bone, compose the best diet for ferrets.
 
A primary reason dogs are poor analogs for ferrets eating bone is because
they have undergone significant morphological changes to their mouth and
throat during the process of domestication.  The dental arcade in most
dogs has significantly changed compared to wolves (either shorter, wider,
longer, narrower, or some combination), and the base of the skull has
changed in many breeds.  Not just the width or length of the mouth is
important in swallowing, but also the angle at the back of the throat.
Even minor changes to the basilar skull can shift the angle of the hyoid
apparatus, a chain of tiny bones that link the tongue and the larynx to
the skull.  The base of the hyoid is embedded in the root of the tongue,
and four short chains of tiny bones attach it to the base of the skull at
one end, and the larynx at the other.  Changes in the angle of the hyoid
can potentially have a great influence on how the tongue is suspended in
the back of the throat.  In some cases, these changes may make it easier
for the dog to swallow bones that could lodge in the esophagus.
Ferrets have had many behavioral and some physiological changes due to
domestication, but skull changes have been relatively minor, if at all.
The biomechanics of swallowing in ferrets are virtually unchanged from
the polecat.  Additional evidence can be found in the cat, domesticated
for the same primary reasons as the ferret=97for ratting and mousing.
While some of the modern fancy breeds of cats have considerable changes
to the skull and dentition, most others do not.  "Mongrel" cats have the
same biomechanical ability to consume bone as their wild progenitors.
Considering the success of cats to return to a feral state and the number
of wild small animals they consume, as well as the propensity of pet cats
to hunt while outdoors, it is obvious they eat bone regularly and safely.
Because the purpose and morphological changes wrought by domestication
are quite similar between cats and ferrets, and the biomechanics of prey
consumption are relatively unchanged, it is therefore probably safe to
assume that domestication has not altered the biomechanics of bone eating
in either species.
 
Ferrets are unique in one respect.  Like cats, they dine alone, hide
while eating, and eat slow and leisurely.  Like dogs, they have a
deep-rooted instinct to gnaw on the bones left over after consuming the
organs and muscles of their prey.  The reason for both lies in the
economics of predation and the hunting niche occupied by the polecat.
It is the evolutionary history of the polecat that governs the feeding
style of the ferret, including the desire and ability to consume bone.
 
Bob C
[Posted in FML issue 4155]