How could a rat be setting off a coon trap. They aren't heavy enough. Mice and rats can go in and steal the bait but they won't set off the trap. If you have foxes around, that is what is setting it off and not getting caught. Coon traps are usually 30 inches long and a fox is long enough that he can grab the bait, the door comes down and hits him on his butt, and he simply backs out. I have to use 36 inch long traps to catch foxes. This time of year, coons are looking for protein so any meat type bait should work well. Any scraps off the BBQ are best like chicken bones, steak bones or anything with a BBQ smell to it. Fish type baits work better in the spring. Sweet baits are notoriously good for coons any time of year. Keep the trap off the ground so skunks don't get in. Skunks can't climb so even a foot off the ground works fine. Make sure the trap doesn't rock around and is set firmly on what ever surface your setting it on. A trap that moves when an animal steps on it won't catch as much. If you are using the two door Havahart traps, they are worthless for coons. They aren't big enough to hold a large coon and when a coon is caught in one, they can roll the trap over and the doors simply fall open and the coon walks away. Safeguard cage traps are the best on the market. Coons have a hard time tearing them up and I've caught over 1000 coons and never had a single escape.