Makes sense out in "nature" -- fur on body totally
insulates him (yes, easier to say him than him or her!).

However, in a home, with electricity and fans, you can
turn up the fan enough that it drives the air right
through the fur and onto the skin.

(A/C maybe not so helpful in cooling dog, UNLESS there
is a close-by fan pointed right at him, because of
that insulation.)

My dog, when we come in from a hot day's walk, is of
course panting, but if I turn on a fan pretty high,
he'll go plop down right in front of it, maybe 2 feet
away.

Anyway, friend still insists that dogs cool themselves
(maybe 99%) via their TONGUE!, don't you GET it?

---

Just wondering what you guys think, and what kind of
arguments YOU'VE been in on this subject.

Thanks!  Waiting to see what you say.

If the environment isn't air-conditioned, a fan doesn't  do much to
actually cool the dog once the temperature gets to the upper 90s.....
Too close to the dog's normal body temperature,  which is between 100°
and 102° F.  This applies to humans as well.  The fans just blow hot
air.

It has been discovered that a Few dogs have sweat glands in locations
other than their feet, but the coats still hold the heat in....  I have
had one of these dogs with multiple sweat gland locations, and when I
wove my fingers into his coat, I could feel the moisture.  It certainly
didn't seem to keep him cooler.

After Desert Storm, Saudi Arabia wanted to start using sniffer dogs to
evaluate baggage and commercial air shipments.  It wasn't well known how
well this would work for the dogs, as the primary location they'd be
working was a huge metal building with very large fans stirring the hot
air.  Pre-trained dogs were brought in, some Labrador Retrievers and
German Shepherd Dogs.  In the test phase, half of the dogs were kenneled
in air conditioned kennels, and half in shaded ambient temperature
kennels.  They expected that the dogs who were in air conditioning while
off duty would work better and longer..... because this holds true for
humans.  However, they discovered that the dogs kenneled in ambient
temperature kennels worked better and longer.  Go Figure!  They had some
degree of heat aclimatization.

One good thing to help a pet owner tell when heat is "too much" to
continue exercise is the tongue itself.  If the tip or sides curl upward
while panting, it's time for a break and a cool-down.  Most dogs doing
some activity they love... chasing balls comes to mind....  will not
realize that they Must stop because they are overheating, so it's up to
us to stop it for them.  Mine love to enjoy a good barking and
fence-running frenzy.... so I sometimes have to confine them to our deck
to control/reduce this.

When you spray the dog with water from a spray bottle, spray it in the
groin and lower abdomenal area and in the "arm pits" of the front legs,
and even the chest.  The large blood vessels and lungs can do a better
job of cooling by evaporation, since these areas have less coat.
Wetting the coat elsewhere on the body  is helpful ONLY when the water
is moving.... a hose or shower spray pushing coat aside.  Wet coat holds
water against the skin and the water simply gets warm and sits
there..... not cooling at all.  We sometimes need to apply Cold to the
groin and "arm pits" to a slightly overheated dog.... and for this we
use regular bottled water that is "iced" or that is frozen.... and get
the dog into air conditioning.  Ice water in the drinking bowl is unsafe
for the overheated dog, but it can be cooled down with an ice cube or
two for an entire bowl.  Many dogs enjoy chewing up ice cubes, and by
the time that small amount of water goes down, it's sufficiently cooled.
Given the choice between a carpet or dog bed and a tile, linoleum or
wood floor, dogs will select the uncovered floor, over on top of or in
front of an airconditioning vent.  

Note that wet terrycloth on a dog or a human holds the heat in; when I
competed in synchronized swimming in high school, we practiced in the
late evening, when the pool's open-swimming was over.... while waiting
between routines, we wrapped up in wet towels.  When I experimented with
wet towels on my Dane, in Texas, within a few minutes the side toward
the dog was warm.

Gel-filled cooling coats that we use down here cover the dog's underside
only.  Gel-filled crate mats can also be helpful.... IF the dog will lie
down on them; some won't.... but they at least do help keep the feet
cool.  Many of us have battery operated fans that we hang on our crates
in our vehicles or training areas, and use special reflective tarps for
deep shade.