Evaporation helps keep a dog cool by using a cooling vest.

A doggie cooling vest uses evaporation to keep Fido cool

Here is Fido, looking both sharp and cool as he sports the latest in fashionable dogwear that also keeps him cool on a hot day. Fido is wearing a "cooling vest", where the owner wets it down, places it on the dog, and the properties of the evaporation process help the dog stay comfortable. 

This is similar to the way that a swamp cooler works in dry environments to lower temperatures in a home. As evaporation occurs, heat is needed and thus cooling occurs.