How does evaporation cool plants and animals? why is evaporative cooling important?

Water has high specific heat capacity which enables it to remove large amount of heat from other surfaces without changing state. When water absorbs heat from other surfaces, it makes the surfaces feel cool, when water has absorb enough heat, it will evaporate from the surface, leaving the surface cooler.
Evaporative cooling is important because it helps to regulate the temperature of the body through sweating.