Hi, I'm Robin D. Owens and I write fantasy romance for Berkley-Penguin-Random House (the "Heart" Series – 13 going on 14). I also write the Ghost Seer paranormal romance series for Berkley (Ghost Seer out last April, Ghost Layer recently released in September and Ghost Killer out next February). I wrote a five book series of fantasy for women (the "Summoning" series) for Luna Books.
I'm known for my animal or Familiar companions, and I'm quite sure that Zanth, the telepathic cat with attitude (redundant), sold my first book, HeartMate. Since then, in the Heart books, I've had kittens, cats, dogs, foxes, a raccoon and a hawk as my Fams – along with a wandering mole, etc.
In my Summoning series I have some magical beings who shapeshift into various animals. Miniature greyhounds and warhawks are the most common, though occasionally they have their catlike moments. I also have flying horses.
These characters are in the books for several reasons: mentors, friends, comic relief and occasionally under threat (they can get into trouble and some go to war). In the Summoning books, they also play a mysterious part in shaping the worlds' events.
You might call them archetypical characters. Mentors who advise (and may have their own agendas which also make them tricksters). Friends who are there to listen or nudge or nag (so, that's still a horse word but at least it wasn't badger...). Comic relief: this I use quite a bit, I like my tension built, released and built again.
The Ghost Seer series has a ghost Labrador as a spirit guide and all around cheerleader.
Things to watch for when you're writing animals. First, my cats are pretty much cats, except they are slightly more intelligent and can speak telepathically. They are self-centered, they live in the moment, they have contradictions in whatever philosophy they have but it has meaning to them at the time. They're vain. They call all cats "Cats," capitalized, and all dogs "dogs," NEVER capitalized. They look down on dogs. And they negotiate payment for favors.
I try to keep my animals close to what they are here on earth, and with those limitations. My puppy in Heart Thief adores her FamWoman...and piddles on the rug. My crippled and starving Noble Hound in Heart Fate resents having to eat leftovers that a hunting cat "generously" gives him. He looks down on cats because they aren't as loyal as dogs. The Ghost Seer dog, Enzo, is determinedly cheerful.
For research...I have cats and my ex-roomie had a puppy. I observed. There is a strategically vital place in my house and each and every one of my cats has found it and held it.
I read a lot of books on foxes and there are some in the neighborhood. Another thing, THE expert on foxes call a noise they make "chortling." Maybe the sound is closer to chortling than the standard, well-known "barking." If I used "chortling," it would pull my reader from the story to think about the word which is not something associated with foxes....
The mole came in handy in a couple of the stories and a fan who liked moles and stuck the idea in my head provided critique and tips.
I have friends who have horses and I studied "natural" horsemanship, went to a horse camp (I live in the city) given by another writer who has Lipizzaners.
So, from my point of view, don't make them too cute, or too smart, and keep them lifelike. People will love them anyway.
May all your writing dreams come true.