Radiator fan comes on often
 

Hello everyone.

I've got a 2007 Mazda 3 hatchback.
I have question regarding the radiator fan. When I start the car in the morning, turn on the heat, and the engine is cold, I notice that within 1 min or so the radiator fan will turn on for a few seconds and turn off. It will continue turning off and on during the entire drive or unless I turn off the heat.
My question is why does the radiator fan come on when the engine is cold? Should it not come on only when the engine gets too hot? Is this normal for Mazda?

Thanks.