In general, the ant traps out there tend to be fairly safe for our pets. They are usually more of a foreign body threat than a toxicity problem if ingested, but nonetheless I recommend keeping them out of reach of your cat. Some people also state success using borate or diatomaceous earth and say they are fairly safe. You will also want to be sure you keep any of your cat's food off the floor and try not to leave excessive amounts in the bowl as this could attract the ants. They do make special bowls that have a water reservoir around the food part, to keep ants away or you can do the same thing by putting your cat's food dish in a pie plate with about 1/2" of water in the bottom.
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