Every now and then, animals find their way into my writing. The current book I’m writing, Kringle Through the Snow, has a highly intelligent Newfoundland named Shadow Lord. The other book I’m writing, Carrying Light, has the preternatural cat Bergeron. The last book I wrote, Kringle on Fire, has a not-so-bright orange cat named Doofus.
At this point I’m supposed to talk about why I put animals in my stories. I think humor is a big part of it. Shadow Lord is so big and so well-behaved, yet he still detains Sierra long enough for Wade to talk to her. Doofus loves everyone like a drunken bro, even the child in the middle of his terrible twos. Bergeron flies — sometimes causing a traffic jam, in front of people who are not to know of her existence.
If I had to find a similarity among these pets, it’s their ability to communicate with humans. In pet-like ways, of course. Except for Bergeron, who speaks with telepathy to other telepaths. How many of you would like a telepathic cat? I’m not really sure myself. How many interruptions a day would I tolerate, especially if the transmission is “I’m starving! I can see the bottom of my food dish!”?

I should mention that another reason to include animals is because it makes protagonists look more soft-hearted. Unless the pet is a wolf, and then it accomplishes exactly the opposite.
Animals as characters can make for fun in writing and in reading. I’m going to have to write them in more often. Kittens, anyone?