Dogs like humans can't get rid of the heat by sweating, instead they pant. Panting results in the evaporation of the dog's saliva from its tounge, which further lowers the temperature in that part, due to the absorption of heat during evaporation. During Summers, when its very hot, the dogs pant excessively, thereby expelling there heat.
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1) dogs do not have sweat glands like human beings
2) they pant because as the saliva evaporates , it cools them down .
3) evaporation taken into chemical reaction in points of view is when atoms goes to a higher energy level, they will break into bonds during evaporation
4) when this occurs the breaking of bonds will release energy thus cooling dog down
5) it is very high in hot summer days because of high evaporation .

hope i helped u my frnd .
thank you , :-)
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