Last night, Elizabeth read the FML with the toothy comments, and I just
couldn't *eschew* making a few comments.  (ho ho) Sorry I've forgotten who
wrote the original comments; I'm not trying to be impersonal.
 
The measurement of teeth and skulls to determine speciation and biomechanics
dates back to the Natural History years of the early to mid 1800s (I
capitalized Natural History because back then, it included all the subfields
we now call astronomy, biology, chemistry, anthropology, etc.) Initial work
in morphometrics was done by such scientific greats as Owens, Huxley, and
Darwin (to name just a few), and much recent work has been done by Von Den
Dresch, Marcus and Clutton-Brock (to name even fewer).  One of the best new
books is Leslie Marcus 1996 "Advances in Morphometrics" Plenum Press, NY.
It costs somewhere in the $100+ range, but worth it.  For simple
measurements, I reccommend Angela Von Den Dresch 1976 "A Guide to the
Measurement of Animal Bones from ARchaeological Sites" Peabody Museum of
Arcaheology and Ethnology Bulletin #1.  She specifically demonstrates how to
measure teeth and jaws.
 
Regarding the comments about ferret canines, yes they are long.  But are
they longer, in proportion, to other carnivore teeth, and the answer is, not
in animals in their size range.  What you have noticed is an allometric
relationship between the size of the predator (and prey) and the
biomechanical strength of the tooth itself.  In simpler terms, the bigger
the animals (and prey), the thicker and shorter the tooth in proportion.
You have to exclude some specialized animals from the equation, such as
narwhales.  walrus, elephants and saber-toothed predators, simply because
they *not* typical.  It would be like using funny cars to judge the
performance of a mid-size economy car.  One is obviously souped up and they
don't compare, and their exculsion is correct.
 
The way a predator kills its prey is probably the major factor in the length
of the canine, especially in non-primates.  Sexual selection is probably
more important in primates for the size of canines, but then, they aren't
chasing down zebra for meals.  Large carnivores typically kill by
eviseration (tearing out the vital organs while the animal is still alive)
or more commonly by a choking hold to the throat (Often, in pack hunting by
wolves or lions, both occurs at the same time) Teeth have to be powerful to
withstand a quarter ton of excited zebra pulling you all over the
Serengetti, as well as able to crush the neck and other anatomical
structures.  In comparison, the saber-toothed carivores hunted what is
called megafauna, or giant animals--at least when compared to those found
today.  They used the long sharp canines to stab the necks of the animals in
an effort to bleed them to death, and it worked; saber teeth have evolved
independantly at least three times, in both marsupials and mammals, and
perhaps even in the Reptilia.
 
Small carnivores are usually solitary hunters, with a few exceptions, and
they can't hang on to a neck while the rest of the pack dispatches the prey.
They usually kill by a bite to the head or neck in an attempt to crush the
base of the spinal cord.  This results in an almost instant death for the
prey, reducing the chances of predator injury and increasing the chances of
a successful hunt.  The teeth have to be a little bit longer to do this,
proportionally, than in the large predators.  A linear relationship exists
between the size of the predator and the size of the canine, so the smallest
carnivores, like least weasels or short-tailed weasels, have the longest
canines when compared to house cats or gray fox.
 
As for ferrets, if compared to the canines of weasels, skunks, opossums,
mink, polecats, etc., they are either proportional or slightly smaller.
They are not much longer in proportion to house cats, I might add.  One of
the reasons they look longer is the structure of the ferret's face forces
the upper canines out of the mouth, while a cat's facial strucure keeps the
upper canines mostly or completely within the mouth.  They look longer, but
proportionally, they are pretty close although the ferret's is slightly
longer (and from my calculations, significantly [=statistically] different).
 
One of the characteristics I am looking at for the differentiation of ferret
skeletons from polecat skeletons is the changes in teeth wrought by
domestication, and I have been specifically looking at canine length as one
of 122 variables I am testing.  Because of the preliminary nature of the
study, I can't say if significant differences exist between polecat and
ferret canines, so won't mention anything.  Some might object to that
stance, but after fighting the myth of an Egyptian origin for the ferret for
so long, I don't need to start a new urban myth regarding the size of ferret
teeth- "Bob said they were shorter..."
 
Bob C and 20 MO Furbytes
[Posted in FML issue 2105]