Rodents and roaches: How Metro Detroit ranks, and how pets can help (or not)

Good news: The chance of spotting a roach or rodent in a Metro Detroit home is well below the national average.

The bad news: There is a chance.

Plus, what dogs and cats can do to help ...

This first appeared in ClickOnDetroit's Data Drop newsletter. Sign up here.

Pest sightings in American homes

In the United States, roach sightings (11.3% of households) were slightly less prevalent than rodent sightings (11.9%) nationwide. In Metro Detroit, those figures were 1.3% for roaches and 6.5% for rodents. This is according to data from the U.S. Census Bureau's American Home Survey conducted in 2019.

Here's the frequency of pest sightings for the 15 most populated metropolitan areas:

Roach and Rodent Sightings by Metro Area -- U.S. Census Bureau, American Housing Survey, 2019 (U.S. Census Bureau)

Why more rodents than roaches in Metro Detroit?

The Census survey points out differences between homeowners and renters and between geographic locations. Roaches are more common in renter-occupied units and units in the American South, while rodents are more common in owner-occupied units and units in the Northeast, including northern Midwest regions such as Metro Detroit.

The changing seasons in our region is the primary reason we don't have a more severe cockroach problem. Look at the warmer Houston region, for example: A similar rodent-sighting rate (6.8%) as Metro Detroit (6.5%), but an astronomical cockroaches sighting rate (35.2%) in relative to Metro Detroit (1.3%). That makes me feel like Houstonians are just trampling roaches every morning on their way to the bathroom. No thanks.

Because they are cold-blooded organisms, insects such as cockroaches do not survive very well in extreme cold or hot temperatures. Experts say they won't develop or reproduce when temperatures are below 45 degrees F or above 115 degrees F. So be thankful for the winter -- it keeps the insects, cockroaches in particular, away from us.

Rodents, meanwhile, thrive in the regions with higher density. That's another thing to be thankful for -- space to breath in Detroit and its surrounding communities. We're not as dense as the Boston, Chicago, Philadelphia or Washington regions. But we do have trash, and wherever there is trash there are rats and mice. And that is a problem as old as civilization.

Worldwide, rats and mice spread more than 35 diseases. These diseases can be spread to humans directly, through handling of rodents, through contact with rodent feces, urine, or saliva, or through rodent bites. Diseases carried by rodents can also be spread to humans indirectly, through ticks, mites or fleas that have fed on an infected rodent. Moreover, rodents destroy property, spread disease, compete for human food sources, and are aesthetically displeasing. They prey on older structures and can stick it out during the cold much better than insects.

The CDC suggests some simple tactics to help keep rodents away: Preventive actions include sealing up access into homes and businesses, removing debris and heavy vegetation, keeping garbage in tightly covered bins, and removing pet and bird food from their yards.

Seems obvious, but you know how it goes. All it takes is one of your neighbors to drop the ball on trash day(s), and suddenly you start seeing rats in your neighborhood. Don't be that neighbor.

How to get rid of them

The expand on that, here are four approaches to getting rid of cockroaches (per the CDC):

Prevention: Inspecting items being carried into the home and sealing cracks and crevices in kitchens, bathrooms, exterior doors, and windows. Structural modifications would include weather stripping and pipe collars
Sanitation: Deny cockroaches food, water, and shelter. These efforts include quickly cleaning food particles from shelving and floors; timely washing of dinnerware; and routine cleaning under refrigerators, stoves, furniture, and similar areas. If pets are fed indoors, pet food should be stored in tight containers and not left in bowls overnight. Litter boxes should be cleaned routinely.
Trapping: Cockroach traps can be used to capture roaches and serve as a monitoring device. The most effective trap placement is against vertical surfaces, primarily corners, and under sinks, in cabinets, basements, and floor drains.
Chemical control: If you have to use chemicals, that means those other three methods were not applied correctly. But if you have to, insecticides are available. You'll have to contact an expert in this department to be safe.

Cockroach (KSAT)

Getting rid of rodents, however, is actually more difficult. The Military Pest Management Handbook explains why:

"Rats and mice are very suspicious of any new objects or food found in their surroundings. This characteristic is one reason rodents can survive in dangerous environments. This avoidance reaction accounts for prebaiting (baiting without poisoning) in control programs. Initially, rats or mice begin by taking only small amounts of food. If the animal becomes ill from a sublethal dose of poison, its avoidance reaction is strengthened, and a poisoning program becomes extremely difficult to complete. If rodents are hungry or exposed to an environment where new objects and food are commonly found, such as a dump, their avoidance reaction may not be as strong; in extreme cases of hunger, it may even be absent."

Here are steps to take to get rid of the rodents:

Eliminate food sources: As mentioned, you have to stay on top of your trash. This requires proper storing, collecting, and disposing of refuse. Don't be a slob.
Eliminate breeding and nesting places: Remove rubbish from near the home, including excess lumber, firewood, and similar materials. The CDC says these items should be stored above ground with 18 inches of clearance below them. This height does not provide a habitat for rats, which have a propensity for dark, moist places in which to burrow. Wood should not be stored directly on the ground, and trash and similar rubbish should be eliminated.
Construct buildings and other structures using rat-proofing methods: Well, again, this is why rodents love old buildings. If you're building a new structure, however, you can use materials that will help keep rodents out. Rats can gnaw through wooden doors and windows in a very short time to gain entrance. All holes in a building's exterior should be sealed. Rats are capable of enlarging openings in masonry, especially if the mortar or brick is of poor quality. All openings more than ¾-inch wide should be closed, especially around pipes and conduits. Cracks around doors, gratings, windows, and other such openings should be covered if they are less than 4 feet above the ground or accessible from ledges, pipes, or wires.
Killing programs, trapping: Do you have a cat? Cats can help keep the rodents out. Cats can be effective against mice, but typically are not useful against a rat infestation (more on that below). There are rodenticides that can be used, too, but you'll need a professional for that. There are over-the-counter rodenticides, but that sounds particularly dangerous. Personally, I'm not a fan of handling chemicals and poison if I don't have to. I'd "rent" a cat or something first. And then there are rodent traps -- I've seen so many handcrafted ones, including the drowning bucket. One thing to note about trapping: To be effective, traps must be monitored and emptied or removed quickly. If a rat caught in a trap is left there, other rats may avoid the traps.

Cats vs. rats

Ah yes, the great cats vs. rats battle. Apparently, contrary to what you might think, cats are really bad at handling rat populations. Darn.

From Phys.org in 2018:

The first study to document interactions between feral cats and a wild rat colony finds that contrary to popular opinion, cats are not good predators of rats. In a novel approach, researchers monitored the behavior and movement of microchipped rats in the presence of cats living in the same area. They show the rats actively avoided the cats, and only recorded two rat kills in 79 days. Published as part of a special "rodent issue" in Frontiers in Ecology and Evolution, the findings add to growing evidence that any benefit of using cats to control city rats is outweighed by the threat they pose to birds and other urban wildlife.

"Like any prey, rats overestimate the risks of predation. In the presence of cats, they adjust their behavior to make themselves less apparent and spend more time in burrows," says the study's lead researcher Dr. Michael H. Parsons, a visiting scholar at Fordham University. "This raises questions about whether releasing cats in the city to control rats is worth the risks cats pose to wildlife."

Plainly put: Rats in big cities are usually too big and strong for cats. Scaredy-cats.

That doesn't necessarily mean the presence of a cat in your household won't keep a rat away. But don't expect your cat to hunt a rat. Depends on the cat, I guess. I have lived with a handful of cats in my life, some much braver than others.

Cats vs. cockroaches

Yes, cats will eat cockroaches. If they can catch it, they might eat it. Hopefully the roach does not contain harmful parasites that could sicken your cat. Usually it is completely harmless for your cat to eat a roach.

But again, anyone with experience living with cats knows it depends on their mood and the cat. And cats are pretty smart about what they do or don't eat -- they have their own self-preservation instinct about food. A roach may be on the menu, but that doesn't mean they'll eat it. They could kill it for fun, though. Cats do that.

Bottom line: Just having a cat in the house probably will help keep the roaches away, but whether or not they can help actually exterminate roaches is another story.

What about dogs?

Certain dog breeds are instinctively rat hunters and killers. The Terrier, for instance, was once used in the "rat-baiting" blood sport back in the old days. Terrier breeds (Bedlington Terrier, Fox Terrier, Jack Russell Terrier, etc.) have instincts to hunt and kill rodents such as rats.

New York City residents have been known to use these dogs to fight the city's rat problem. This is from a July 2020 report by Fox 5 NY:

Late Thursday night into early Friday morning, Richard Reynolds led a group of six rat hunters working six terriers of varying breeds into and around the trash cans, trash piles and construction sites of the Lower East Side in search of this city's most reviled occupants.

"If things work right, and [they don't] always," Reynolds said, "they should catch the rat, shake it vigorously, break its neck and move onto the next one ... We do [this] for the dogs. But doing it for the dogs doesn't attract much attention. Killing rats attracts a lot of attention."

They've made a sport of it. Is your dog up to the task? I bet not, unless you are actively training them to do so.

Yorkshire Terrier (Pixabay)

As for cockroaches, dogs are kind of like cats in this scenario. They might eat one, sure, as a crime of opportunity, but they aren't going to help you get rid of a cockroach population. Still, you could train your dog to kill cockroaches -- from CockRoachZone.com:

"Dogs can keep cockroaches away, but they're not effective against established populations or heavy infestations. In small numbers, dogs can deter new cockroaches from settling in your home. With persistence, you can even train your dog to kill cockroaches on sight."

I feel like if you have enough cockroaches around that you find yourself training your dog to kill them, you might want to take a step back, regroup, and get to the root of the problem. This sounds kind of fun, sure, but come on now. Get those cockroaches out of here already! Someone, please.

Previously:

Rat Bite Disease