Under the common law, cats are considered "personal property" and for the most part the legal rules that apply to personal properties – from handbags to hamburgers – apply pretty comfortably to cats as well. However, because cats are living creatures, some rules don't apply well at all.
That's because cats, like all animals, do at least three weird things that non-living properties don't: they move themselves from place to place; they make independent decisions about what they want to do; and (given time and the friendly assistance of another cat) they can replicate themselves.
While there are plenty of other weird things about cats (please insert your favorite personal anecdote here), those particular three make a mess of the law's attempts to treat cats exactly like handbags or hamburgers.
For instance, with respect to property ownership, the law normally looks at who has "custody and control" of a piece of property – yet cats (as cat owners well know) brook no patience with people who try to control them, and can rival the slipperiest of international jewel thieves in attempts to keep them in custody. That's part of the "making-their-own-decisions" problem.
Two, with respect to the abandonment and conveyance of property, the law normally looks at things like the "voluntary relinquishment of possession" – yet cats, which do very well at conveying themselves, thank you, may or may not acquiesce in being relinquished, and may or may not be in agreement (or even around) when the owner decides it is time for the cat to have a new owner. That's part of the "move-themselves-from-place-to-place" problem.
Three, with respect to the value of property, the law normally looks to what a fair market assessment would be – yet cats seem to increase their value to their owners the longer the owner and the cat are together, including by magically producing odd furry things called "kittens" out of themselves. In other words, a curious aspect to cat companionship is that cats and the little cats that come from cats appreciate rather than depreciate in value, quite the opposite of cars and computers. That's part of the "replicating-themselves" problem.
All of this is simply to point out how flexible and forgiving the law must be when it comes to holding people responsible for what cats actually do. Until that remarkable day arrives when we decide to include cats themselves in our legal rights system (and thus create cat jails and cat bankruptcy proceedings, among other problems), it remains cat owners whom we tend to hold tightly to some rules – while at the same time conveniently releasing them from others.
In Multnomah County, for instance, cats are deliberately excluded from code definitions of "animals at large", so there is no obligation (under the code anyway) to physically restrain a cat on the owner's premises or to keep one on a leash (good grief, as if you could anyway).
Yet the code also says that "any person who finds and harbors a cat without knowing the owner's identity" is supposed to notify animal services, furnish a description, and – if the finder chooses to hang onto the cat – publish a notice in the newspaper to inform previous owners. The fact that – in a county of hundreds of thousands of cat owners – you rarely see such notices is as much a reflection of the realities of cat ownership as it is a reflection of what people think about complying with County code.
On the one hand, it is certainly admirable that County code attempts to penalize owners for leaving a cat unattended for more than a day without minimum care; for depriving a cat of proper facilities, or for physically mistreating a cat.
On the other hand, it is just plain silly that County code declares that a) cats must be licensed, b) that the person who licenses the cat "becomes" the owner and is responsible for the action or behavior of the cat, c) that owners are not allowed to permit their cats to trespass upon another's property, or d) that owners are not allowed to permit their cat to unreasonably "cause annoyance, alarm or noise disturbance to any person or neighborhood by barking, whining, screeching, howling, braying or other like sounds".
A "cat license" for a cat owner is about as necessary and helpful as a "microbe license" would be for a sick person, and would justify about the same level of responsibility as to effect upon others. And indeed, who ever heard of an owner "permitting" their cat to do anything? Most cats permit their owners to pet them and to feed them, and the consent abruptly ends there. In fact, it is cat owners who are most likely to cause annoyance, or to whine loudly, or who should perhaps be licensed, ideally after a full psychological examination and stringent physical fitness test.
As cats whimsically transport themselves from one location to the next, making their ridiculously independent decisions about what happens to be on their wish list for that day, and popping out this kitten or that as the mood strikes, it is the law that follows them around doggedly, sniffing here and there for some scent of how to keep track of them, and how to control them, and, if necessary, how to hale them eventually into a courtroom where they can – finally – be placed under oath and explain to the jury, if they can, just exactly what happened to the sausages right when the phone rang.