Seems I have more online time than I thought, so I thought I would punish
all of your for it.  HA!
 
Blame this next part on BIG (and others).  Yes, I'm returning to the "Yawn
Thing." This thing has started to bug me as much as the question I was once
asked in a human evolution class "Why does human hair grow nonstop, while in
all other mammals, it has a set length?" (No one knows) The idea about
scruffing lowering the oxygen levels is a good one, and may be a factor in
dogs and cats, but ferrets have an internal common carotid in their neck
region, rather than the interior and exterior carotids found in most
mammals.  This allows their neck to bend in any direction without pinching
off the flow of blood to the brain.  The ferret windpipe is also strongly
reinforced for the same reason, and it would take one hell of a scruff to
collapse it anyway.
 
BIG's ideas about mating and play rituals are also good.  I haven't observed
much sex-play in ferrets so I can't be certain, but I haven't noticed much
yawning in other mustelids during procreation.  (I have often thought it was
a female human response, based on years of experience...) Probably not the
reason.  The same can be said of dominance play.  In dominance play, showing
teeth can be seem as a threat, so the loser probably wouldn't do such a
thing.  Winner maybe, but the loser?
 
Other ideas e-mailed include "they are just waking up" and "scratching
causes their mouths to water" to "the CO2 in your breath stimulates the yawn
response." My favorite was "Bob, you are so longwinded that you bore them to
tears, and all the others yawn in support." All good ideas; there were
others less good.
 
Personally, I think the yown response is similar to the leg jerks you get
when you scratch the ribs or lower back of a dog.  Its like a glitch in the
wiring; stimulate the right spot and the beastie does something weird
someplace else.  (Now that's a straight line if I ever saw one).  Ferrets
seem to have two of these spots, one being the head scratch/yawn response,
and the other being the butt scratch/lower extremity paralysis thing.  This
also works with dogs and cats; just scratch hard on the lower spine near the
butt, and the fert will walk off only using the forelimbs and dragging the
lowerlimbs.  The paralysis only lasts as long as the scratching takes place.
It may be the scratching stimulates the nerves to such a degree that motor
responses are unable to get through.  (I have noticed many predators tend to
bite the lower back region of larger prey prior to killing them, and it may
be an attempt to cause lower limb paralysis to avoid being kicked, or the
animal escaping.)
 
The yawn seems to be stimulated when the ferret has the top of it head, its
neck, or the sides of its head scratched.  Some seem to yawn more than
others, but all seem to do it.  Hard scruffing of the neck also seems to
cause the response, although at a lower frequency.
 
In mustelids the two major muscles that close the jaw are the masseter and
the temporalis.  The masseter starts on the zygomatic arch--the bone just
below and behind the eye--and gives our friends their cheeky appearence--
and ends on the lower jaw.  The temporalis starts on the top and back of the
head at the nuchal crest, following the sagital crest to just behind the
eye.  It passes under the zygomatic arch to attach to the lower jaw.  This
is the muscle that makes the male head look so round, especially in hobbs.
There are also some neck muscles that attach to the jaw, making the closing
bite quite effective.  In addition, these muscles tend to be of the
"fast-twitch" variety, giving the ferret the ability to give a fast and hard
bite.  Scratching the head may cause these muscles to depolarize or contract
to a minor degree, but enough to stimulate the yawn response to stretch out
the fibers.  Or it could be an autonomic nerve response to the scratching
stimulation.  But who knows?  It may be me after all.
 
I want to thank all of you who have flooded my mailbox with posts concerning
my mother.  She is doing better, but her stroke was severe, and she will
need surgery to unclog her carotids.  Right now she is kind of loopy and
pissed off...come to think of it, she has always been that way; now she just
looks it.  I plan on returning to Missouri later this week , then returning
to Ca-Ca land prior to the surgery.  After that, I will return to the road
and ferret visits, so you nuts in the northwest should see me in a few weeks.
 
Bob and the severely yawning 14 plus 1
[Posted in FML issue 1599]