If you live in the U.K., Ireland, New Zealand, Malta, Norway, Switzerland, Austria, Croatia, Italy, Portugal, or some municipalities in the United States, the law of the land requires your pets to be microchipped.

Mandatory microchipping is also the way for dangerous dogs in Colorado, Minnesota and Virginia (though in Virginia, a tattoo will do).

We all know microchips keep animals safe by helping lost pets get back to their owners. To municipalities it also translates into less strain on municipal animal service facilities, and helps tag serious offenders so there’s no mistaking an animal’s true identity. But a microchip isn’t foolproof. This we also know.

Lost pets are not necessarily scanned for a chip, even if they’re found and impounded. Chips don’t always make themselves known (studies on this have demonstrated serious lapses in microchip identification, especially in overweight animals). And these devices have been known to migrate to unpopular locations so that even assiduous scanning doesn’t necessarily yield results. Some scanning devices are technologically inferior or unable to identify certain other companies’ microchip frequencies. And sometimes even microchip-carrying pet owners are ignorant enough to fail to have their pets’ microchips registered to their personal digits, in which case the pets’ encoded ID has no way of getting linked to their loved ones.

Here’s the upshot: Even if an owner goes to great lengths to have a microchip installed, and then registered (a big “if”), a shelter or veterinarian may not bother to scan the body for a chip, they may not use the correct scanning device (a plethora of devices abound), they may not find one if it has migrated to an inaccessible location or the animal’s obesity obscures it …

These have been the industry’s historical stumbling blocks as chips make their way towards widespread acceptance. Add to the mix a large dose of unhealthy, obstructive competition among microchip manufacturers and marketers (think Clash of the Titans in miniature), and you might wonder how the industry has managed to succeed at all over the past decade or two.

As if all that negativity and insecurity wasn’t enough to tip the scales on this technology’s adoption, there’s a new factor to fear: microchips may not only prove useless … they may also cause cancer.

We know it’s absolutely possible. We know of at least one case where the pathologists agree: Léon died from a lethal fibrosarcoma cancer which emerged from the exact location of the microchip. Other cases have not been so clear as Léon’s, but several have now been documented. And now that a peer-reviewed paper has been authored (Microchip-Induced Tumors in Laboratory Rodents and Dogs: A Review of the Literature) we might be hearing a lot more about this risk  in the future.

Which is not such a bad thing given that every single bit of information is a good thing. If there’s a risk of cancer I imagine most of my clients will want to know about it before I install the thing. So I’ve taken to doing so. And once I explain that it’s currently estimated to be a tiny risk, all my clients have decided it’s worth it. After all, they’ve said, if losing Buddy is even just ten times more likely than the cancer, I’ll take the chip and take my chances.

Still, not everyone agrees. Privacy advocate and microchip cancer study author Dr. Katherine Albrecht is near-rabid on the subject. Though she admits that reports of cancerous microchip reactions are very few and far between, she argues that the FDA does not demand reporting and therefore suggests the problem is more widespread than we currently understand.

Though she stops short of urging owners to surgically explant the chips, she wants all pet owners informed of studies that tie cancer in rodents to microchips, and urges policy makers to "reverse all policies that mandate the microchipping of animals under their jurisdiction or control."

In response to the elevated volume of the discourse on the subject, the AVMA flatly opined with the following statement:

Tumors associated with microchips in two dogs were reported, but in at least one of these dogs the tumor could not be directly linked to the microchip itself (and may have been caused by something else) … the risk that your animal will develop cancer due to its microchip is very, very low, and is far outweighed by the improved likelihood that you will get your animal back if it becomes lost.

In other words, until we’ve devised something better to help get your pet back after he’s lost, consider the microchip a highly flawed but low-risk backup to your pet’s ID tag. Unless you’re assured of never losing your pet (and who among us can claim this degree of certainty?), I’m afraid the microchip will have to do. I still say: Go without one at your pet’s peril. But rest assured, I will never back a policy mandating microchips for all pets. For all they have the potential to offer, I'll nonetheless stop way short of calling them risk-free.

So now it's your turn … what's your take?


Dr. Patty Khuly

Art of the day: "my kat...synsyter gates" by y-it's mom.