Getting Rid of Black Rats

I honestly understand that asking the forum to help me solve my problems might be a bit tiring for you. But I just want to get as much knowledge as possible to get to a viable solution. I have roof rats (Rattus rattus) in the neighborhood and at night they come to mess around in my backyard. I am definitely not using commercial poison, and I’m thinking about using castor beans. Is this a good idea? Or should I do something else?

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Why would you prefer to use castor beans over commercial rat poison? Castor beans are much more toxic and thus a greater safety risk if a nontarget organism (e.g., pet, child) were to “take the bait”. I imagine the effects of secondary poisoning would also be greater. And castor beans presumably have a bitter taste, so the rats may be less inclined to consume the poison.


in Australia at least, most of the commercially sold rat poisons are second-generation anticoagulants; anything that eats the rats, like owls, are also killed, usually horribly. There’s a lot of campaigning to ban them, but many popular stores still sell them unfortunately


I understand, but this is likely to be magnified using castor beans as ricin is one of the most toxic known substances. I know approved poisons have their risks and drawbacks, but using unapproved poison is not the solution. I recommend traps over poison.


depending on where you live, rats may just be an inevitable part of the landscape. if they’re common in you’re neighborhood, you’re not going to be able to seal yourself off from the rest of the neighborhood, and you’re not going to be able to kill all the rats in your neighborhood. so in such a case, maybe the best case scenario is not to a rat-free backyard, but having fewer rats in your backyard than in the rest of the neighborhood.

if your backyard is one of the favorite places for your neighborhood rats to hang out though, you probably need to figure out what is attracting them and remove whatever is attracting them. for example, if you’re spreading birdseed in the backyard for birds, and the rats are coming for the leftover seeds, then maybe you could feed the birds less seed or stop feeding the birds altogether. or if the rats are there because the neighbors leave a lot of food trash in their backyard, then you might need to talk to your neighbords to fix the problem.

one method that a lot of people have used to successfully reduce rats is keeping one or more good rat-catching cats and / or dogs. however, not every cat / dog is going to be a good rat catcher or can be trained to be a good rat catcher, and free-roaming cats are not appropriate in all environments, since they can also indiscrimiately kill other animals besides your problem rats.

the problems with trying to control rats with just poisons in general is that you end up killing animals that eat poisoned rats, and that poisoned rats can end up dying and decomposing in unexpected places that are hard to reach – in walls, in attics, under floors, etc.

and then when you use unorthodox poisons like castor beans, you create other problems. i don’t know how you would prepare a ricin-based poison that would kill only rats. i would think that a rat is generally going to avoid eating straight castor beans, but then if you infuse some sort of tasty food with such a poison, you’re going to be killing anything else that might also find such a tasty treat. in some places, law enforcement people might even look suspiciously at people processing castor beans for use as poison.

it’s better to trap rats so that you can see what you’re catching and control how and where they are disposed of. if there are a lot of rats to deal with, you can make a relatively simple and effective trap out of a 5 gallon plastic bucket, and there are commercially available versions of such traps, too. often the way these work is by drowning the rats, which is sort of a nasty way to die, but no less horrible than poisoning.


Cats are notoriously dreadful at killing rats, despite a few cat owners claiming otherwise. A terrier is quite effective, but of course, if a food source remains, the rats will come back.


a trained terrier can be effective, especially when working with a human. but untrained terriers can indiscriminately kill, just like cats can.

your study is of random feral cats. a cat picked and trained specifically for killing rats is going to be a better rat catcher than a random feral cat, just like a trained terrier is going to be a better rat catcher than a random untrained terrier. cats and dogs have their pros and cons. cats have greater reach and autonomy, but may never learn to be selective in their killing. dogs can be super effective when paired with a human, but may be less effective without a human partner.


Agreed up to this.
I was looking at this and wondering whether I should say something about this that might not be very much acceptable or effective.
Keep the rats away.
Removal of Food, water and habitat.
Add ons: Keep all types of seeds, fruits, or pet food in Cans with tight-fitting Lids, empty or cover any outdoor water containers/sources

Blocking the Entry points with cloth, steel wool.
Using Repellants: Ultrasonic Repellents and Natural repellants e.g Plant Mint, Citronella, using essential oils such as eucalyptus oil, clove oil, and cinnamon oil, peppermint oil, chili powder, Cotton balls soaked in vinegar.
That much.

Regarding other points:
Never use Glue traps.
In India:
A man was arrested who was seen moving his motorcycle to and fro and crushing a rat under the wheels for creating public nuisance.
A man allegedly killed a rat by tying its tail to a brick and drowning the rodent in a drain.
A police complaint was filed by an animal rights activist and the accused was booked by Police under Prevention of Cruelty to Animals Act , mischief by killing or maiming cattle, etc.
So check this before doing anything else other than to repel the rats.


There are a number of designs of live trap available which allow you to release non-target animals unharmed. You can humanely kill the black rats you catch or maybe release them in an area where you know there are owls and/or snakes.

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Ricin is so toxic it is regulated under chemical/biological weapons laws, please be aware of legal issues and be aware of the fact that you are replacing one poison with a likely worse poison, I’m really not sure why you would use ricin as a poison alternative, it’s a dangerous poison


I find this scenario somewhat far-fetched. I love cats, I have one myself, but a special trained ratting cat? There is a reason this doesn’t exist outside the realm of imagination.

I did work at a barn with my boss’ French bulldog, utterly untrained, who was quite good at ratting, incidentally. And cats do not “have more autonomy” than dogs.


Get your hand on a few grey rat snakes and see your problem disappear.

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Number 1, make sure all food sources and shelter are not available.
Is there a possibility that a snap trap would also kill non-target species? If not, a big snap trap doesn’t have a detrimental on predators, and is more effective than other traps.

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the environment in the scenario was a backyard. anything is possible, but i would imagine it would be difficult to seal off a backyard from rats.

this is a good point to specify that whatever control methods are used should probably conform to whatever laws, mores, and norms are in the community.

i wouldn’t transport invasive species to other locations to let them become a problem somewhere else, and unless you know that your rats couldn’t have come in contact with poisons, i wouldn’t take the risk of introducing a potentially poisoned rat to a place where the resident wildlife don’t normally encounter a poison risk.

training would involve acclimating the animal to its home base (and to life outdoors, if it’s not already used to that), sociallizing it, and teaching it a routine (mostly for feeding it). then, just as you would a dog, encourage hunting behavior by using positive reinforcement, and once it’s hunting, then ideally you would want to positively reinforce only kills of target prey (but as i noted, cats may never learn to be very selective).

picking the right cat is important, too. you’ll increase your chances of having a good ratting cat if you can get a kitten from a proven working cat. some folks say that female cats are better for catching rats than males. there are some breeds that have better base characteristics (larger size for larger prey, long coats for dealing with cold environments or shorter coats for hotter places, more social cats tend to be easier to train, etc.), but each individual will vary in personality and life experience (baggage), too.

this is in the context of working as rat catchers. alhough cats may enjoy human company, most cats don’t need much human involvement other than feeding and medical care. most dogs i’ve encountered are much happier being / working with people or in some other group (with a herd, with a pack), rather than being left to themselves all day.

i would modify this to “encourage native predators” (by providing habitat for them). beyond domesticated species like dogs and cats – and even then, only when used approrpiately – i wouldn’t introduce non-native species to where they don’t belong, and i probably wouldn’t take a native individual from wherever it is to another location (especially of unknown habitat quality) just for the purposes of rat control.

yes, snap traps are indiscriminate. my impression is that they are not paricularly effective against rats, but if you were to use one, i think you would want to use it in a place where nothing else but the target pest would happen upon it.


Thought for any holes in the boundary wall of the backyard (if any) from where the rats may enter from neighbor’s backyard. Anyways, No issues. Your first reply covered all the aspects.


I kid you not, I seriously believe that Dominican cats have been selectively bred for higher predatory instincts. I know of one in particular… she would come triumphantly into the house with the tail of a skink, eat it, then go back to where she last saw the rest of the skink and catch and eat it, too.


I’ve heard that those poisons are banned here in Mexico, though.

I’ve tried that many years ago and rats outsmart them (both Victor traps and catch-and-release traps). With persistence, they will fall in but anyway, if we are considering cruelty, snappers are quite cruel.

The thing with my neighborhood is that it is not even a suitable place for other wildlife. Here in Mexico most houses are stuck to each other and have tiny concrete backyards. There are no snakes or owls (well, only sometimes) that might eat the rats. There are cats, though…

I had not thought about these, I’m sure there aren’t sold commercially, but I could make one.

Cats can have a rat in front of them and ignore it.

Not always, but recently they appeared to be nesting in some messy, almost dead, ferns I had. I got rid of them by now, but I’m sure the rats will keep coming.

My neighbor’s dogs do kill any rat that appears home, she also has had rats nesting inside their house in the past, which she poisoned…
But my situation is that there aren’t any other animals that could be indiscriminately killed by the dogs (they never catch birds as cats do, and there’s nothing else than birds and rats, so rats are the only thing dogs kill).


Indeed, I do not have other food than tender shoots in my yard. But a neighbour has dogs and dog food for free, where doves and grackles gather every day.
I am always very sceptical about the efficiency of repellants. Are you sure those things work?
Regarding killing rats, I’m in Mexico, so police won’t care about rats. And those events in India were quite cruel and cynical murder, not an attempt to get rid of a pest.

Oh, but I do agree with you about glue traps. Rats will only carry them on their backs as backpacks, and they do kill native wildlife (lizards, geckoes, snakes, bugs, birds, frogs, whatever) alike or more than rats.

@bouteloua Thanks for correcting the title. Just another careless, very funny mistake.

How can I humanely kill them, since I would never release them?

I think you are all right about that, I had thought that maybe as an organic poison it wouldn’t pollute as much when the dead rat is decomposing, but not a very strong argument…

Exactly. You can more easily train a bee.

Exactly. Grey rat snakes don’t live in my area, but getting a boa is a bit more possible, but a very wild idea (and it would eat a rat every month). Backyards here are tiny and made out of concrete, so having predators isn’t as easy.

At least that’s easy. I can confidently assure that only rats would fall in. But indeed, rats outsmart them quite often

Yeah, they climb the walls.

Recently one cat tried to catch a grackle, and it was harassed intensely by the flock (I was sleeping and they woke me up).

I would find the biggest Victor-style snap traps I could find and try those first. See if those might be effective. If you’re concerned about birds or other non-target animals getting snapped, place a cover of some sort over the trap to narrow the access route and reduce that chance.

In Hawaii, they put metal flashing around palm tree trunks to keep rats from climbing into the palm fronds. Don’t know if you have a situation where rats are climbing to get into places you don’t want them, but it’s a solution to consider.