How to address animals?

Do we address animals as objects (it) or by their gender just like we do to humans (he, she)?

I see cases of both widely used. This is what I can make out.

If the animal is known, we are in best position to refer the animal as a he or a she, based on the gender. 

My sister has two pugs, the boy is called Coco and the girl is called Cola. We refer to the dogs as per their gender.

Now if we have a case of an unrelated animal, use of "it" is best suited. 

The dog was barking all night, it was probably sacred of the fire crackers.