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Written by Admin
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Thursday, 24 November 2005 |
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Page 5 of 11
A common misconception is that dogs do not sweat. Primarily, dogs regulate their
body temperature in a completely different way, through their tongue. That is
why after a dog has been running or on a hot day, its mouth will be seen wide
open with the tongue hanging out. This is a very efficient form of cooling in
terms of maximizing heat lost while conserving moisture, because it carries heat
from the hottest part of the body, the interior core of the thorax, compared to
sweating, which cools the already coolest part of the body, the skin. Besides
being intuitively correct, this higher efficiency of thermal loss in terms of
moisture conservation stems from heat flow being proportional to temperature
gradient in a given system. In addition, dogs effectively sweat through the pads
of their feet, since they are not furred. Again, on a warm day and after
exercise, a dog's naturally wet footprints might be visible on a smooth floor.
Dogs possess a rete mirabile in the carotid sinus at the base of their neck, a
complex of intermingled small arteries and veins which acts as a heat exchanger
to thermally isolate the head, containing the brain, the most temperature
sensitive organ, from the body, containing the muscles, where most of the heat
is generated. The net result is that dogs can sustain a high degree of physical
exertion over a prolonged time in a hot environment, compared to animals which
lack this apparatus; thus, a dog chasing a jackrabbit through the desert may not
be able to outrun the rabbit, but it can continue the chase until the rabbit
literally drops dead from overheating.
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About Dogs 
