• Chelle Hartzer

Tom and Jerry Reruns (AKA: I really don’t hate cats)

What do the old Tom and Jerry cartoons, Speedy Gonzalas, and Garfield all have in common? The mice were good at what they did and were never caught. In a mad twist of life imitating art (you can discuss with me later whether cartoons are art), a city has released thousands of cats to control the rodent issue they have. What could possibly go wrong?


You may have seen this posted recently in the news and on social media and it’s worth taking a closer look at it and not just laughing it off. First of all, using multiple methods to control pests is best. I had someone challenge me a couple weeks ago and told me that method “X” was the only way to go and it worked. Well, that’s not true. This article does not reference any other rodent control methods that are being employed, but let’s hope they are looking at reducing sanitation issues, eliminating habitat, baiting, and trapping along with the biocontrol method of using cats.

The article claims that using these cats is “environmentally friendly rodent control”. Two things to dispel here, cats are really not great at controlling rats, and cats are extremely environmentally unfriendly to native birds and other small animals. Let’s start with the wildlife issue. While it is impossible to know for sure, research estimates that in the contiguous US, upwards of four billion birds are killed each year. Add to that as many as 100 million reptiles and amphibians. These feral (and domestic) cats are non-native species killing off billions of wildlife annually. They are even bad for endangered species.


As for cats being good at rodent control… well… sort of. A study out of Europe showed that they predominantly brought back rodents to their human hosts. However, only one of those rodent species was the Norway (or brown) rat. All the other small rodents they captured were native mice, voles, and squirrels. Fully grown Norway and roof rats are large rodents, and predators will typically go for smaller, easier to handle prey when given the choice.

It does state that cats do not typically eat rats (true) but that their presence is a “deterrent” to the rats. There is some evidence to support this, but not nearly enough. One study reported that male house mice "exposed to cat odor did not show any response habituation to the cat odor and became more aggressive, increased mark urine production and were more attractive to females". So they almost did better with cat pheromones nearby! Additionally, rats are smart, if they realize that something is not a threat, they will start to ignore it, especially if there is a good food source nearby that they are attracted to. Rats are also known to change their behavior patterns to avoid competition and threats. Instead of being mostly nocturnal, in high populations they will switch to foraging during the day. Cats, also mostly nocturnal and known for sleeping much of the day, just won’t have the opportunity to catch rats.


Probably my favorite part of this piece is the statement that “owners” of these feral cats provide “food, water, shelter, and wellness to the cats who work for them.” So you feed them, provide them a safe spot, give them water and you expect them to go out and hunt rats??? That’s like delivering a pizza to my house and then saying, “how about you make your own pizza from scratch?” Why would I go out and hunt for food when my food is being delivered right to me?

I am fully in favor that the cats are spayed and neutered before being released: there are too many unwanted, feral cats harming native wildlife. My CFO* has informed me that I should remind people to adopt from shelters and keep cats indoors. She also told me that I need to tell people cats are good as pets, not control… or else she will leave a freshly hacked hairball on my pillow tonight.


That’s some of the science behind cats and rodent control. When was the last time you updated your rodent control program? If you have been having rodent issues and want to improve your program, give us a shout to see how we can help here!



Lagniappe – cats carry a number of pathogens that can be harmful to people, particularly Pasteurella multocida which is found in between 70-90% of cats.

*Chief Feline Officer – Max the cat

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