A snap trap, when used properly, kills the mouse instantly with a snap bar that comes down on its neck or spine. The real problem is that they may not be baited or set properly - and when that happens, mice may be able to grab the bait without triggering the trap... or they may be injured and left to suffer, rather than being quickly killed.
It's only when the mouse is killed instantly that the trap could be considered humane, as the animal dies quickly without experiencing enduring pain or panic. That's why it's important to set traps correctly. Carefully follow the instructions that come with the traps. In addition, below are a few tips to help ensure the trap works as intended.
How to Properly Use Snap Traps
Use as little as you can. If you put down too much, the mouse may be able to grab some without triggering the trap - or the mouse may not be positioned where expected (since the bait is too large) and could be injured or maimed when the trap triggers. Replace bait every day if it hasn't been eaten. Common baits include peanut butter, oats, and cereal, even a bit of tuna. You don't need much for a mouse - and 1/8 teaspoon or a tiny bit more may work. Use as little as you can to still attract the mouse.
Use a piece of string to tie the bait to the trap or press the bait securely into the bait area. This forces the mouse to get in there and work at it a bit to get it.
Don't over-use a trap. Over time, the snap mechanism may weaken. Discard the trap if you notice this.
Set several traps per room. There are usually many more mice than you actually see. Rodents like to use the same paths over and over again. They also tend to stay close to walls where they feel more protected. Put the trap down at a right angle to the wall along the path they normally take, with the bait side up against the wall and directly in their path.
Consider 'pre-baiting' the trap. Pre-baiting is when the traps are baited but not set. Rodents can come up and eat the bait and get used to the trap. After the bait has been taken 2 or 3 times, then the trap is again baited but this time is set. The rodent will already be used to the trap and walk right onto it.
Mice are naturally curious and may not need pre-baiting. Rats are an entirely different matter - they are naturally cautious rather than curious, and pre-baiting will likely be needed.
Check the traps regularly. If you find a mouse still alive in the trap you will need to kill it to end its suffering (a good reason to do everything you can to make sure the trap works as it's meant to).
Be sure to wear hen disposing of a dead rodent. Try to avoid touching the body. Take the trap outside and hold it over an outdoor garbage bin. Pull back the snap rod and let the body drop right into a plastic bag in the garbage. You can then wash the trap with soap and hot water and re-set it. w
There are many brands of these traps, with one of the most popular being the mouse trap. Regardless of what brand you use, be sure to always read and follow the directions.
Also be sure to keep these traps securely out of the reach of children and pets. You may need to disable and remove them during the day if children and pets are in the area. The trap can also be covered with a large box (make sure there's enough space above the trap to allow it to snap) with holes cut into either end. The holes must be large enough for the rodent to enter freely. The trap needs to be placed far enough into the box so that a curious child's arm or an inquisitive paw cannot reach the trap.
Even though many people would prefer not to have to kill mice at all, there are many challenges to humane rodent pest control. Figuring out how to get rid of house mice can be a challenge, particularly if the infestation is serious. If it comes down to it, mouse snap traps are significantly more humane than some methods, especially the well-known sticky glue mouse traps.