Q: (Private E-mail): Can[male] ferrets really get caught on wire cages?
 
A: Its hard, but possible.
 
Male ferrets, like nearly all mammals, have a bone in the penis called the
bacula (or if you prefer, baculla, baculum, bacullum, bony penis, Os penis,
Os priapi, penile bone, or, my personal favorite, Der Penisknochen.  Oh,
yeah, my favorite bacula author is a guy named Pocock.).  The preferred
usage listed in the Nominal Anatomica is "os penis." Many female mammals
have an homologous bone called the Os clitordis.
 
The bacula is a common ancestral trait of mammals, and in the species it is
missing, it is concidered to be a derived trait.  In other words, the
mammalian default is to have the bacula, and in a few species, the bacula
has been lost through evolutionary processes.  Most notably, it is missing
in humans (not apes; even the chimp has a bacula) and large terrestrial
mammals, such as elephants, horses, and ungulates.  The form of the bacula
is specific to mammal, so it is important for species identification.  It
also changes during the lifetime of the mammal, so it is important in the
determination of age for mammals.  While some authors feel the major
function of the bacula is for mantaining the ability of the guys to do their
thing, most now feel it is to maintain the integrity of the urethra.  In
other words, it helps to prevent the kinks that might interfer with the
male's contribution to society.  Some authors think the curved or hooked end
is important in the mechanical stimulation of the female, causing a release
of eggs.  This would tie in well with ferrets, having an induced ovulation.
 
In Europe (and to a smaller degree in the USA) collecting baculae is
concidered an honorable hobby.  In the southern USA, raccoon baculae were
(and still are) carved into pointed toothpicks.  They have been used as awls
in basketry by Native Americans, and in bloodletting by both Americans and
Europeans.  Whale baculae (1-3 feet long) were often used as clubs, while
those of sealions and bears were used as awls, wedges, and sharp pointed
fighting implements (Spear tips).  They have been used as fasteners and pins
worldwide.  My favorite use was by some south Americans who pierced their
noses and ears, inserting baculae from various species.  The baculae from
river otters and dogs were preferred.
 
As stated, the shape of the bacula varies among mammals, being long and
slender in one, and short and curved in others.  In the ferret, it is about
1 1/2 to 2 1/2 inches long, and strongly resembles the end of a crochet
hook.  The end is slightly curved, and the tip is sharply hooked.  There is
a small flaired knob on the end.  The bacula connects to the pelvis by a
strong ligament.  The main portion (bacular shaft) can be above,
surrounding, or below the urethra, although in most mammals it is below and
slightly surrounding the urethra.  Normally the tip is embedded in the
erectile tissues of the glans penis.
 
This is the problem with ferrets and wire cages.  Even with wire of smaller
mesh, the tip of the bacula can accidentally push through the mesh and get
caught.  This is both frightening and painful, so the animal tries to
escape, which can entrap it even more.  If not freed, the bone can fracture,
or the penis can be seriously damaged.  I might add that damage to the
bacula is common; the worst case I've seen was from a bear who's bacula had
broken mid-shaft, twisted, and turned at right angles to the rest of the
bone, then healed.  Once for a paper, I surveyed 28 wild mink skeletons, and
discovered damaged bacula in 8 of them.
 
Problems with damaged bacula's include (but not limited to) damaged erectile
tissues, cut or torn urethras, communated fractures where the bone sticks
out of the penile tissue, and gross amputation.  Longer term problems can
include difficultly or pain on urination, inability to mate, and infections.
The urethra can become blocked or kinked by swellings on the bacula, or by
scar tissue forming secondarily after being damaged by the bone.
 
If the reports I am aware of, most bacular entrapments occur while climbing
wire mesh cages.  A small portion occurred on wire mesh flooring, and one
occurred on a wiffle ball.  Still, overall, it is an infrequent occurence.
Prevention by laying linoleum on wire floors, and by having as large a wire
mesh as possible on the sides of the cage seems to prevent almost all
problems.  The wiffle ball can be considered an anomaly and ignored.
 
Mo' Bob and the 18 Mo' Ferreteers
[Posted in FML issue 1847]