Changing a CAT into a DOG

Can you solve this word puzzle?

C A T
_ _ _
_ _ _
DOG

Start with CAT.  Change 1 letter in each step, changing it to a different word.  E.g. you can put CAB in the first row of blanks.  Whatever you put, it must be a word.  Can you get to DOG in just 3 steps?

Here is our solution.  Did you get it?

C A T
C O T
D O T
D O G