"Does your cat eat mice?"

It's a question I ask frequently at preventative care visits, even in reference to indoor only cats.

The answer is usually a vehement, "Oh no. We don't have mice in our house."

Kitty and I exchange a silent, knowing look.

Sometimes the owner's answer is more ambivalent. "Well, she catches them, but she doesn't actually eat them."

Kitty's look says, Aren't my humans so cute when they're in denial?

Jimi Happy Hendrix quickly and efficiently devours a mouse he caught.

Unless the cat is also having gastrointestinal symptoms of occasional vomiting and colitis, I may not press the issue at this point. It's hard enough to convince most cat owners that not seeing mice is not proof they don't have mice breaking and entering their home. It's even harder for owners to accept that their bored-looking, lazy indoor feline might be a secret agent, snuffing out rodent invaders without their knowledge.
Having witnessed my own kitty efficiently gobble down an entire mouse in less than 60 seconds, not catching your cat in the act of ingestion and/or not finding half eaten mouse corpses is not a reliable indication of what your cat doesn't do. Indeed, I've always considered cats the most effective and user-friendly kind of mouse trap available!

The subject of what makes the best mouse trap came up recently when we discovered evidence of a rodent invader in our break room kitchen. Finding a partially eaten chocolate bar with teensy weensy tooth marks was proof positive we had a mouse in the house.

After we got over the collective horror of knowing a mouse had been scurrying over our silverware, we pondered how in the world a mouse got inside. Like most homeowners, it was hard for us to swallow the idea that we don't occupy an impenetrable fortress! And it's hard to admit that even very clean kitchens can sustain a rodent - at least for a while.

A "walk the plank" homemade mousetrap

Once we wrapped our heads around the fact we do indeed have a rodent problem -- even a single mouse is a problem in my book -- we turned our thoughts to how to eradicate the invader from our midst. Everyone had an idea ranging from sticky traps (see "It's Not a Deterrent, It's a Medieval Torture Chamber") to a homemade bucket of doom that reminds me of a terrible miniature version of the game show Wipeout. Loving and caring for animals on an instinctive and professional level made the idea of allowing our mouse pest to suffer by drowning or starvation unbearable. In fact, last summer the clinic staff rescued and released an injured field mouse found in the clinic parking lot. What if our uninvited guest was actually little Gus-Gus from last summer? (Highly improbable, I know.)
Putting out rat poison was a no-go for us for several reasons:

1. Poison pellets have a tendency to wander away from the bait box, becoming a potential toxic threat to unintended animals like dogs. We didn't want to "drum up business" by inadvertently poisoning our patients.
2. Worse, because traditional poisons bio-accumulate in birds of prey if they eat enough ailing tainted rodents, the newer bromethalin rat poisons work more quickly and devastatingly. Accidental ingestion of these newer poison baits by dogs and cats is terrifying because there is little that can be done to treat the toxicity! (see "Of Mice and Mayhem: A Rodenticide Story")
3. Mice typically don't take the bait and die out in the open where you can easily clean up. On a purely selfish level, we were opposed to living with a foul-smelling decomposing rodent in one of our clinic walls.

While traditional mousetraps are messy and a bit scary to set up, they are a humane method of eliminating unwanted small rodents. There are modern variations on the spring-loaded wire and wood mousetrap, but this type of trap invariably works by snapping shut forcefully enough to break the mouse's back while he's grabbing the bait. The pros of this type of mousetrap include 1) death is instantaneous for the mouse; 2) the dead mouse is easily retrievable; 3) collateral damage is minimal for dogs and cats that set off the trap inadvertently. The downside is that you're left with a dead, sometimes mangled mouse in your living space.

In researching mousetraps for this blog, I learned there is a type of trap that quickly electrocutes any mouse who meanders through a pet and kid-safe corridor to the zapping chamber. This sounds like a humane method of execution, and the trap is reportedly easy to clean out. A downside is that battery operated units may not be reliable for long-term applications like vacation homes. I can just imagine the charge running out of the unit and the mice enjoying a free-for-all of the bait inside!

For animal lovers, an attractive option to discourage mice from wanting to share our space in the first place is an electronic device that emits an unpleasant sound audible only to rodents. Unfortunately, reviews of this type of deterrent method are not highly favorable. One major downside is that over time rodents become accustomed to the "noise" and just ignore it as they scurry about stealing your food, destroying your soft goods for nesting material, and excreting their hazardous wastes all over the place.

Dr. Kim finds our rodent invader caught safely in a live trap.

On a lark, we decided to implement the best kind of mouse trap we had at our disposal: a lovable, Siamese cat named Joey who came to work with his CVT mom that day. Although Joey did not accomplish his mission in the brief time allotted, it somehow felt fair and right to invite one of our domesticated companions to assist in the day-to-day struggle to keep rodents at bay. Cats need to hunt to live psychologically balanced lives. For many cats the hunt is an effortless, graceful exercise in patience, timing and athleticism. And, finally, as understanding of feline nutritional need evolves, rodent eating can be seen as a healthy, natural alternative to high-calorie, high-carbohydrate dry kibble. Encouraging predation behavior in our indoor kitties is a win-win situation. In the best case scenario, you won't even know your cat has been doing her job for you. With that possibility in mind, however, I do recommend occasionally deworming against tapeworms and other parasites.

Veterinary assistant Ashley Stanton releases our mouse pest.

In the end, we resorted to a live trap loaded with some tasty bait. Once the mouse wandered into the inescapable chamber, we oohed and aahed over him a while before taking him outside for release. Although, the live trap instructions advise releasing the rodent two miles away, we didn't have that much time or motivation. At the edge of a neighboring field, we carefully opened up the trap lid and waited to see what would happen. That mouse didn't miss a beat! He hopped over the edge of the trap, scooted into the tall grass and burrowed into the snowy ground cover. Just like that, he was gone.

Will we regret our decision to catch-and-release this crafty rodent? Maybe. But for now, we're just glad to be rid of the little pest in a humane, mess-free way!