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The fine line between 'pets' and 'pests'

For shelters, there’s a necessary inconsistency between the treatment of adoptable rodents and those raiding the pantry

From Animal Sheltering magazine July/August 2013

Rats and mice can make sweet pets, but the wild ones can cause trouble in your facility. The best way to deal with them humanely is to make sure they have no way to get into your building in the first place. Humane Wildlife Services field supervisor Lori Thiele seals an opening in a building, ensuring that raccoons won’t be able to get in. Rats and mice can get through much smaller openings, so you have to check your facility thoroughly for holes. Defunct plumbing—and even some functioning plumbing!—can be an entry point for wild rats. If your shelter’s lunchroom is regularly piled with dirty dishes or unsecured food—in the cupboards or the trash can—you’re hanging out a welcome sign for rodents. Live trap

The shelter John Griffin visited a few years back was providing a temporary home to many animals—cats prowling and napping in the cages, occasionally sticking a paw out to bat at a visitor; dogs chowing down or excitedly waiting for their walks; and, living in the walls of the shelter, hundreds of rats.

Like other wild animals, rodents are always looking for a safe, warm place to raise their young, and in the older, drafty building, they had found an ideal hangout. “It had gotten to the point where sometimes a rat would just walk across an office while staff were meeting,” says Griffin, director of Humane Wildlife Services (HWS), a service of The HSUS that specializes in nonlethal resolution of wildlife conflicts.

It’s not uncommon in shelters. Years ago, after a particularly wet season, Lollypop Farm in Fairport, N.Y., had a big problem. “In the middle of the day you could look at some of our fences and the problem areas, and there’d be anywhere between 50 and 100 rats that you could see,” says Joanna Dychton, farm manager. “And whatever you can see? Multiply that by two or three times.”

Warmth and large amounts of food being stored make shelters prime real estate for the savvy mice and rats who live among us. Unfortunately, a permanent, one-time solution is not really feasible, says Griffin, who advises ongoing monitoring and prevention strategies.

And you do need to prevent it. Rodents running loose around a shelter, digging into food supplies, excreting wherever they go, can cause serious problems: health risks to animals and humans, damage to equipment and supplies—and damage to public perceptions of the shelter, which may cost adoptable animals homes.

Dychton, whose shelter maintains a small farm animal petting zoo that many locals visit for fun, notes that facilities that are inspected—by the health department, by insurers, by the Occupational Health and Safety Administration, or in her case, the USDA—will have trouble if inspectors find evidence of rodent feces. Lollypop was hearing enough complaints from worried visitors that it finally decided it had to use a pest control company. “It was one of those situations where we said, ‘We have to get ahead of this, and then what can we do from this point on to be as humane as possible?’” Dychton says.

Dychton didn’t like doing it, and other shelter directors who’ve dealt with the issue hesitate for the same reasons, feeling the inherent tension over opting to kill wild animals in order to protect domestic ones. Few who’ve interacted with friendly mice and rats will find the idea easy to swallow, and even those who don’t have a yen for the squeaky may have legitimate concerns about introducing lethal traps or poisons into the shelter environment.Ideally, you shouldn’t be faced with that choice. Experts emphasize that the best solution is to avoid attracting wild rodents in the first place. You can manage the issue in a way that doesn’t conflict with your organization’s animal welfare mission—but the kindest measures are most effective before you have a problem. Once rodents are in, truly humane options are limited. Preventive measures will keep you from losing sleep over the difficult ethics of killing the wild cousins of the adorable little guys running in their wheels in your small-animal room.

The Best Offense is a Good Defense

To the pets inside your building, your shelter should be a comfortable, healthy, relaxing environment. But wild rodents should find your facility impenetrable from the outside, and uninviting within. Envision them having squeaky little planning councils, warning each other, “One does not simply walk into Mordor.”

First step: Don’t let them in. Second step: Give them no reason to stay. If you get rid of all possible points of entry into your facility and remove all sources of food, water, and shelter, rodents will likely head for greener pastures.

A mouse only needs a tiny opening—about the diameter of a dime—to make himself welcome. In wintertime, rodents are attracted to the heat escaping from a building—so not only is that draft making shelter staff shiver and raising your heating bill, it’s serving as a neon “Welcome!” sign to local wildlife.

To keep your halls rodent-free, you have to find and fix all possible points of entry, both on the interior and exterior of the building. Pay particular attention to the building’s foundation and the area around it; places where pipes, cable, wires, and other utilities enter; and places where siding or the building’s façade have deteriorated. Older buildings, especially those that have gone through extensive renovations, can offer underground entry points through defunct plumbing and voids from the original structure. Doors that don’t quite meet the floor, and attached garages where animal control vehicles come in and out, are another potential culprit.Once you’ve identified all possible points of entry, seal them. Plug any cracks around drainpipes, vents, and other small openings with wire mesh (HWS recommends 16 gauge Stuf-Fit copper mesh; 19 gauge if it’s unavailable) or quick-drying cement. (Don’t use caulk, rubber, or plastic fillers; rodents can chew through them.) For small openings that don’t involve electrical wiring, use expanding foam insulation; if possible, place steel wool or copper mesh—pan scrubbers can be useful—inside the hole before adding the sealant (a product called Xcluder works well). For larger openings, ball up galvanized window screening and stuff it in the hole, then finish with caulking or cement. Cover the edges of doors and windows with metal to prevent rodents from chewing through.

You should also try to minimize vegetation overgrowth near the building, keeping bushes and shrubs trimmed up from their bases and nearby walls by at least 12 inches. Not only will this eliminate convenient cover for rodents coming and going, it makes it easier for you to see their possible routes of entry into your building.

Discouraging Squatters

Take a walk through your building some evening—after the shelter’s been open for the day—and try to see it from a rat’s point of view. Is kibble kept on the floor in open bags—or are there pieces of it on the floors, welcoming a rodent to chow down and bring his buddies? Do dripping water faucets suggest fountains for mice to sip from? How about the staff break room? That box of Girl Scout cookies is a beacon of deliciousness to a hungry rodent.

Employees shouldn’t stash snacks in their desks or the lunchroom; garbage cans that smell of lunchtime’s fast-food wrappers need to be emptied at the end of each workday. “The biggest thing is housekeeping,” says Dychton. “If something breaks open, clean it up. Yes, rats can chew through food bags, but usually there has to be something luring them, and open food is a big lure. The more diligent you are with housekeeping tactics, the better.”

As a rule, keep all animal food in secure, rodent-proof canisters like lidded metal garbage cans, raised on pallets if necessary. A better option for those facilities that have it: Keep food supplies out of the shelter entirely and in a separate storage area. Uneaten food should be removed from the cages quickly, and especially overnight.

“You have to incentivize staff to work to prevent these things,” says Griffin. “There really has to be a cultural change to control rodent intrusions.” Regularly remind staff that their willingness to keep the environment free of kibble and leftovers may keep the organization from having to kill wild intruders.It isn’t just food that can suggest a Mouse Motel: Leaky faucets and pipes need to be repaired, and places where rodents could hide or nest—like stacks of newspaper, piles of laundry, etc.—shouldn’t be left accessible. Any such material that can’t be permanently removed should be stored at least a foot from the walls and eight inches off the floor.

When the Champaign County Humane Society in Urbana, Ill., developed a rodent issue, some staff wanted to trap and release the rodents who were roaming the shelter. They gave it a shot, but the live-traps didn’t seem to make a huge dent in the existing rodent problem, says Mary Tiefenbrunn, executive director.

“My shelter manager was getting very frustrated because she was finding mouse poop, mice got into our adopter bags of Science Diet, we had phone wires chewed through, Internet wires chewed through, alarm wires chewed through,” she says.

“We just couldn’t tolerate the damage, the potential exposure to disease. And so we decided that our first responsibility was to run a professional, clean animal shelter that supports the health of our companion animals, and our staff and volunteers, and presents well to the public, and if that means we unfortunately have to go with a rodent control program that involves death, that’s what we’re going to have to do.”

The Less-Mean Means

If rodents are already in your digs, options run from less inhumane to plain awful

While The HSUS recommends exclusion techniques as the most effective means to prevent rodent infestations, once rodents have arrived in your shelter, there is no truly “humane” method of eliminating them—the only options are to relocate them to a strange place (where their chances of survival are slim) or kill them humanely.

With that in mind, here’s what you should know about the less-than-ideal forms of rodent control, listed in descending order from those that can be described as less inhumane, to those of questionable efficacy, to those that are awful enough to fundamentally conflict with the mission of any organization working against animal cruelty.

Keep these in mind, too, if you end up contracting with any pest control company. Not only are some companies more humane than others, but a company that doesn’t plug the holes that are allowing animals into your shelter in the first place is not providing any solution at all. It may kill a thousand rats, but more will return to take their place.If you must remove mice or rats, use live traps. There’s a variety available at grocery and hardware stores, and they simply catch and hold mice rather than killing them. Using them requires a commitment on the part of staff: Once set, they must be checked several times a day to ensure that a trapped rodent does not suffer or starve. Once caught, the animal should either be promptly humanely euthanized using the recommended euthanasia protocol for small mammals, or released into a suitable environment (with ample ground cover and temperatures above freezing) at least a mile away from the shelter. Keep in mind, though, that this is no guarantee the animal will survive; relocating them to unknown terrain puts them at a disadvantage in finding food and shelter.

While not remotely ideal or gentle, traditional snap traps are a better option and less inhumane than poisons, glue traps, and other methods that result in a slow, lingering death. They are more reliably effective and humane when you’re dealing with mice; one source noted that larger rats may walk away with smaller snap traps still attached. When using a snap trap, position it with the trigger next to the wall so that mice can be trapped running from either direction, and ensure that the trigger will snap easily.

Regardless of which kind of trap you use, be sure to bait it with a substance highly palatable to rodents, like peanut butter, fruit, chocolate, or cheese, and locate it next to walls, under furniture, in cupboards, or any place you have found evidence of rodent activity.

Don’t waste your money on ultrasonic devices. Machines designed to repel rodents by emitting high-pitch frequencies have yet to prove their worth. The sounds generally can’t penetrate objects, making them virtually useless for reaching places rodents hide and nest. Moreover, studies have shown that even when exposed to such frequencies, rodents quickly become acclimated. When the frequencies are strong enough to disrupt rodent activity, your adoptable pet rodents will be bothered by them, too—and so may cats and other animals with acute hearing.

Don’t expect much from a feline mascot. Fat housecats are notorious for giving up their mousing duties, and shelters that have indoor kitty mascots tend to experience the same problem. What’s more, feline mascots who get free-fed during the night may actually help attract mice with their alluring kibble supply. To top it all off with a nice dose of weird, a 2008 study indicated that, contrary to expectations, the smell of some cat urine may actually be an aphrodisiac for mice, causing the males to become more aggressive and mate more frequently, and potentially turning your shelter into a rodent singles bar.

Avoid poisons. Most rat and mouse poisons available nowadays are anti-coagulants, and work by causing the animal to die painfully of internal bleeding. Often the animal may ingest several doses of the poison before getting its full effect, and death can take several days, leaving a toxic carcass to be scavenged by other animals who may themselves suffer from the poison. Death can also occur within nests inside a wall or in some hard-to-access location, causing additional problems with smell and decay.

More importantly, having poisons around a facility full of animals can be a safety issue—particularly for dogs, who aren’t exactly picky about what they put in their mouths. While eating one poisoned mouse might not be sufficient to kill an animal, the anti-coagulant in the poison may cause long-term suffering for the cat or dog—or the hawk or owl who swoops down on a mouse they don’t know has been poisoned.

Never, ever use glue traps/glue boards. Glue traps are essentially sticky mats designed to grab the paws of any rodent who steps on them and hold the animal in place until he dies. Animal-loving shelter staff will not want to have to handle one of these traps with a mouse stuck to it, sometimes screaming audibly.

John Griffin of Humane Wildlife Services says that glue traps are the worst of all the options. “If we can only get people not to use those, I’ll feel good about that. They are just awful.”

Barring human intervention, any animal trapped by the glue is likely to suffer a painful death, struggling to the point of exhaustion, sometimes chewing off their own feet in order to free themselves, and likely dying of starvation or thirst at the end. Moreover, the CDC (Centers for Disease Control) has indicated that people should avoid glue traps because the urine excreted by rodents as they lie trapped and dying can contain hantavirus, which can be deadly to humans.


Inga Fricke, director of sheltering and pet care issues at The HSUS, contributed to this article.

Get tips on how to remove an animal from a glue trap.

About the Author

M. Carrie Allan is the senior editorial director at The Humane Society of the United States, served as editor of Animal Sheltering magazine for nearly a decade, and has focused on telling the stories of the animal protection movement for even longer. She holds a master’s degree in English and writing and has won awards for her journalism, fiction and poetry, including recognition from the Dog Writer’s Association of American, the Cat Writer’s Association, the Association of Food Journalists, and the James Beard Foundation (where she was a finalist for the work she does in her side-gig, writing about booze and cocktails for the Washington Post). If you think there’s a connection between her longtime commitment to animal welfare work and her interest in a good drink . . . well, aren’t you the smart one?