I think every story I've ever written had some type of pet in it, even Earth Enchanted did though you didn't get to see him. It wasn't practical for Liv's cat Moe to run from psychos along side of her and so he was left at home. You'll meet him in Wait for the Wind since Liv is (spoiler alert) at home on bedrest with twins for a lot of Ryan's story. Of course in Gypsy Moon, I used Ana's dog Taffy to drive some of the action in the opening scenes, giving Ana a reason to go out into the storm. Circe the cat also gave me the opportunity to show off Ana's magic with small mundane things that would normally go unnoticed.
I love animals, especially cats, so they tend to pop up in my writing without consiously thinking of them. Just there, to give comfort to the hero/heroine, protect, act silly, or whatever. I've always had a pet, usually several at once. Most were rescued from the side of the road where a careless owner had thrown them out or were just born strays. I take them in, feed them, treat for mange (there is a cure for the regular mange, if you need it contact me) and sometimes they just need love to forget the abuse they have suffered. Point is this. Pets stay with you in spirit, love you unconditionally, and devote themselves to making our lives richer. You can ask for a better friend than that.
(in memory of Panther (nano-kitty) It's been twenty years since I lost my best friend. I still miss you.)