(Knightley 2 years 4 months 2 weeks 1 day old, Apollo 1 year 3 months 1 week old)
I have been reading a fair bit on the topic of heat stroke and the particular dangers for assistance dogs. Here in Canberra the summers are usually fairly hot, with our hottest days coming in at about 39-40 degrees celcius (102.2 - 104 degrees fahrenheit) and many days in the mid 30s. Occasionally we have days in the low 40s (up to about 107.6 degrees fahrenheit), which are really horrible.
However, when it comes to keeping a dog cool, we have one blessing; we are really really dry. Go a couple of hours west of us and you are in the beginnings of what is known as the 'outback', ie basically semi desert. Go further west and you hit the real rolling sand dunes type desert. Anyway, keeping a dog cool seems to rest on one main thing, and that is evaporation. When there is already more moisture in the air (otherwise known as humidity!), evaporation doesn't take place anywhere near as well, as it is like trying to put more moisture where it isn't needed! Hence being dry helps keep your dog cool. We do have some humid days, in fact last summer was bizarrely wet and humid, so I need to be careful when working my dogs when we have both heat and humidity. Apollo especially seems to suffer from heat.
So how does it work? Well as I think we all know, dogs lose heat, ie they sweat, through their tongues. This is because their saliva is constantly evaporating from their tongue, cooling the blood that is running through it. As the dog breathes, the hot moisture rich air from their lungs comes up in a breath, and they suck down nice cool fresh air that runs over the tongue and further helps evaporate saliva from the entire tongue surface, drawing cooling air right down into the lungs. This is the main way dogs have for managing heat, however they also lose heat through their nose leather and foot pads.
