Reasons Dogs stuck out his tongue

Although considered to be repugnant to some, but not recognized or dog is a pet is agile and clever. This is evident in several types of house dog that can and have been trained for many things, including when it must dispose of dirt, and so forth.

The problem is, why dogs are often stuck out his tongue?
In hot weather, our skin (humans) sweat, which evaporates, carrying heat to the body through the pores of the skin, while the dogs do not have skin to sweat, then when the weather is hot, hot dog trying to reduce his body with his tongue stuck out there for evaporation on his saliva so that the dog's body becomes colder.