# What's the most humane way of killing mice? **URL:** \ **Category:** Factual Questions\ **Created:** [March 22, 2012, 10:54am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481 "2012-03-22T10:54:56Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Alka\_Seltzer](https://avatars.discourse-cdn.com/v4/letter/a/c89c15/32.png) [@Alka\_Seltzer](https://boards.straightdope.com/u/Alka_Seltzer)\ **Post date:** [March 23, 2012, 9:54am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/61 "2012-03-23T09:54:35Z")
> [@GavinB](#): > > Freezing a mammal to death is completely inhumane and disgusting - and what the hell does body surface ratio have anything to do with how long something dies in a freezer?? It’s basic physics, and will make a huge difference to how long a creature can survive in the cold. If you were paying attention, you’d have noticed I didn’t describe it as humane, I said I wouldn’t make any assumptions. I’d like to hear a cite from a vet. I don’t like the sound of it as a killing method based on **kunilou** ’s anecdote [here](http://boards.straightdope.com/sdmb/showpost.php?p=14891455&postcount=32). Live traps are the most humane, but the mouse may find it’s way back into the house again. Contrary to what some people are saying, house mice don’t exclusively live in people’s homes. They are also found in fields, particularly agricultural land. They won’t necessarily die because they are taken out of a home. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [March 23, 2012, 10:32am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/62 "2012-03-23T10:32:21Z")
> [@GavinB](#): > > Do you realise that none of your analogies are valid because the CO2 used to gas mice is introduced _slowly_ and in certain volumes? It’s nothing like what you described. CO2 is approved by vets and lab technicians the world over, it is certainly one of the most humane ways to go. Far more better than freezing to death. > > Of course an instant lack of oxygen (ie. choking) would be panic inducing, but that’s not how the animals are getting killed. One of the first signs of hypoxia (low oxygen) and hypercapnia (excess CO2) in people is anxiety and restlessness. If the hypercapnia continues a splitting headache, confusion, elevated heart rate, panic and agitation set in. A little bit longer, and you get seizures and coma. Then death. This isn’t instant exposure to high levels of CO2 or sucking on an exhaust pipe, it’s slow and gradual build up of CO2 and lack of O2 in the bloodstream when gas exchange across the alveoli wall is impaired. It’s not pleasant. I don’t at all doubt you that CO2 chambers are used to euthanize rodents. [Here’s a page of guidelines for the NIH in use of the procedure, in fact.](http://knockout.cwru.edu/docs/co2euthanasia.html) I do doubt that it’s the most humane method, however, which was what the OP asked for. ---
**Author:** ![isaiahrobinson](https://avatars.discourse-cdn.com/v4/letter/i/85e7bf/32.png) [@isaiahrobinson](https://boards.straightdope.com/u/isaiahrobinson)\ **Post date:** [March 23, 2012, 10:44am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/63 "2012-03-23T10:44:47Z")
> [@jackdavinci](#): > > Given the lack of cites or even a coherent argument I’m guessing the “house mice have evolved to be stupid if driven a block away” story is some kind of old wives tale. > > Just use a humane trap and deposit the mice somewhere with lots of leaves or other vaguely reasonable shelter. They’ll be fine. Cite [here](http://en.wikipedia.org/wiki/House_mouse#Behaviour) is to a biological journal article. “House mice are generally poor competitors and in most areas cannot survive away from human settlements in areas where other small mammals, such as wood mice, are present.” Also their homing instinct is strong so if you drive it only a block away, it’ll usually come straight back. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 23, 2012, 12:19pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/64 "2012-03-23T12:19:02Z")
> [@GavinB](#): > > Do you realise that none of your analogies are valid because the CO2 used to gas mice is introduced _slowly_ and in certain volumes? How slowly? Hold your breath, and CO2 builds up in your lungs pretty gradually. It becomes very, very unpleasant after a minute or two. > [@](#): > > Far more better than freezing to death. It wasn’t my intention to say that freezing to death happens without suffering - I only intended to show that for a mouse and a person both exposed to the same freezing environment, the mouse will die of exposure before the person will due to a larger surface-area-to-volume ratio. > [@](#): > > Of course an instant lack of oxygen (ie. choking) would be panic inducing, but that’s not how the animals are getting killed. Panic response/suffering has absolutely nothing to do with oxygen concentrations. Here’s another experiment for you to try: get a helium-filled balloon, exhale deeply, then inhale a lungful of pure helium from the balloon, and hold it. You’ll pass out from hypoxia after maybe 10-15 seconds, with no panic, no unpleasantness, no suffering. Lack of oxygen doesn’t cause suffering; it’s the presence of carbon dioxide, no matter how slowly it’s introduced. CO2 causes actual, physical pain in the respiratory tract. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [March 23, 2012, 5:03pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/65 "2012-03-23T17:03:49Z")
The last mouse I caught (a deer mouse; _permomyscus_) I decided to kill by keeping him in a cage and overfeeding him. Unfortunately, after living more than 3 years now, he still hasn’t succumbed… Claiming that mice are house creatures versus wild needs some qualification as to what type of mouse you’re dealing with. My house is inflicted with _peromyscus maniculatus_, which is absolutely a wild mouse, whereas others may only have _mus musculus._ You can probably capture deer mice and release them with a hope of them surviving. House mice, not so much. ---
**Author:** ![wheresmymind](https://avatars.discourse-cdn.com/v4/letter/w/91b2a8/32.png) [@wheresmymind](https://boards.straightdope.com/u/wheresmymind)\ **Post date:** [March 23, 2012, 8:18pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/66 "2012-03-23T20:18:15Z")
> [@GavinB](#): > > Do you realise that none of your analogies are valid because the CO2 used to gas mice is introduced _slowly_ and in certain volumes? It’s nothing like what you described. CO2 is approved by vets and lab technicians the world over, it is certainly one of the most humane ways to go. Far more better than freezing to death. > > Of course an instant lack of oxygen (ie. choking) would be panic inducing, but that’s not how the animals are getting killed. > . Actually, the instant lack of oxygen wouldn’t be panic inducing, and carbon dioxide is one of the worst gasses I can think of if your goal is to kill something painlessly. We don’t sense the lack of oxygen when we’re being choked, we sense the BUILDUP of CO2. If you breathed 100% nitrogen gas, you’d pass out and die peacefully because your CO2 levels would remain low. If you were dispatched with CO2, it would build up in your blood stream and quickly lead to panic and pain. By definition you would need high levels of CO2 to kill a mammal, because you’d need to use enough of it to displace the oxygen in the atmosphere they were breathing. I suspect that the real reason CO2 is used is because it’s cheap and easy to handle, and also heavier than air so it will naturally fill an open container, eliminating the need for a tight seal. If they were really worried about being humane, I would choose something like N2 gas which is cheap and painless, not _the specific gas that the organism relies on to trigger the feeling of choking._ ---
**Author:** ![Autolycus](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@Autolycus](https://boards.straightdope.com/u/Autolycus)\ **Post date:** [March 24, 2012, 6:22am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/67 "2012-03-24T06:22:20Z")
Don’t forget, if we’re going to be truly ethical, we have to eat the mice as well. ---
**Author:** ![benbo1](https://avatars.discourse-cdn.com/v4/letter/b/e19adc/32.png) [@benbo1](https://boards.straightdope.com/u/benbo1)\ **Post date:** [March 24, 2012, 8:22am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/68 "2012-03-24T08:22:21Z")
find a spare tv, put it near their lair, then play ‘the Kardashians’ on and endless loop. They’ll commit suicide. On a serious note, a proponent of capital punishment suggested injection with nitrogen as the most humane alternative (for humans). He explained that nitrogen narcosis, when amped up, is like falling asleep, and eventually the heart stops. They presumably feel no pain. When I heard this, it made me think of those roach bomb canisters. Dunno if they got something similar for mice, but if someone’s that concerned with being humane, maybe drop some nitro canisters in the cupboards, shed, under the sink, wherever. ---
**Author:** ![benbo1](https://avatars.discourse-cdn.com/v4/letter/b/e19adc/32.png) [@benbo1](https://boards.straightdope.com/u/benbo1)\ **Post date:** [March 24, 2012, 8:31am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/69 "2012-03-24T08:31:50Z")
ooops! forgot to add ‘and leave the premises for a few hours’ - it’s fine to kill mice, but the whole point of nitrogen is that it worx on people too. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [March 24, 2012, 9:18am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/70 "2012-03-24T09:18:30Z")
When my cat discovered a nest of mice and brought in five in a row to torture in the living room, I took each one from her by its tail and whacked it off a concrete block in the garden. Infinitely kinder than being slowly ‘played with’ to death. ---
**Author:** ![e72751](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@e72751](https://boards.straightdope.com/u/e72751)\ **Post date:** [March 24, 2012, 11:31am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/71 "2012-03-24T11:31:53Z")
In my experience, snap traps are effective, although I did notice at least once that the trap had moved a fair distance as though the mouse had struggled for a while, which is not nice to think about (it’s possible the snapping made it travel that far though). It’s also not so nice to see blood drooling out of the mouse’s mouth, which happens on occasion. I’m just glad I don’t have to deal with the traps 😉 (someone else can do that). Once one of these little traps caught three mice in one go, which seems quite amazing. I suspect though that a good solution would be to have a cat about the house, because this may stop the mice even staying in the house (one disadvantage though is finding the occasional mice remains in odd places). ---
**Author:** ![Molesworth\_2](https://avatars.discourse-cdn.com/v4/letter/m/9dc877/32.png) [@Molesworth\_2](https://boards.straightdope.com/u/Molesworth_2)\ **Post date:** [March 24, 2012, 12:32pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/72 "2012-03-24T12:32:30Z")
ICBM. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 26, 2012, 11:48am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/73 "2012-03-26T11:48:46Z")
> [@benbo1](#): > > On a serious note, a proponent of capital punishment suggested injection with nitrogen as the most humane alternative (for humans). He explained that nitrogen narcosis, when amped up, is like falling asleep, and eventually the heart stops. They presumably feel no pain. When I heard this, it made me think of those roach bomb canisters. Dunno if they got something similar for mice, but if someone’s that concerned with being humane, maybe drop some nitro canisters in the cupboards, shed, under the sink, wherever. If you’re speaking of actually injecting gaseous nitrogen directly into the bloodstream via a hypodermic needle, then this will not cause nitrogen narcosis; it will instead cause a [gas embolism.](http://en.wikipedia.org/wiki/Air_embolism) Gas embolisms can cause strokes, heart attacks, and a host of other unpleasant symptoms. If you’re speaking of having the subject breathe pure nitrogen at atmospheric pressure, this won’t cause narcosis, either. Air is already 80% nitrogen, so if you switch to pure nitrogen, the partial pressure of N2 will only increase by 25%; you need to increase the nitrogen PP to about 8 atmospheres to induce fatal narcosis. Instead, 1 atmosphere of N2 will result in fatal hypoxia - a lack of O2 in the body, as opposed to a wretched excess of N2. Painless, much better than CO2 - but different from narcosis. ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [March 27, 2012, 8:30pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/74 "2012-03-27T20:30:00Z")
The [enclosed snap traps](http://www.amazon.com/D-Con-00027-Ultra-Covered-Mouse/dp/B000P9URDQ)seem to do the best job for me. The mouse can only approach the bait head-first, so it’s much less likely they will only get a tail or leg caught. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [March 27, 2012, 8:37pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/75 "2012-03-27T20:37:34Z")
Just caught one two nights ago in a snap trap. I was to the trap within 30 seconds and the mouse was dead as Elvis. Clean neck break. I did have one messy death in our last place. Mouse blood is tough to get out of a wood surface. We also ended up with voles there, which are too small for snap traps. I used pellets for them and never saw one again. Re: the peanut butter. It’s an excellent bait, but some mice are so small and careful that they don’t trip the lever. Somebody recommended wrapping thread around the lever and peanut butter so their teeth get caught in it. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [March 27, 2012, 9:01pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/76 "2012-03-27T21:01:51Z")
> [@Molesworth\_2](#): > > ICBM. iITOWTBS. ---
**Author:** ![chowching](https://avatars.discourse-cdn.com/v4/letter/c/f14d63/32.png) [@chowching](https://boards.straightdope.com/u/chowching)\ **Post date:** [March 28, 2012, 10:10am UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/77 "2012-03-28T10:10:17Z")
I have caught a total of 7 little mice within the last four days. I caught them using a glue trap. I am quite creative in finding ways on how to dispose of them but I think the fastest way is to just smash them hard with a shoe. No guts or blood will be splattered. (I have always wondered how is this possible.) If you want to kill a larger mouse just use something larger to smash it with. I can’t guarantee that it will not be messy though. ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [March 28, 2012, 12:52pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/78 "2012-03-28T12:52:10Z")
> [@chowching](#): > > I have caught a total of 7 little mice within the last four days. I caught them using a glue trap. I am quite creative in finding ways on how to dispose of them but I think the fastest way is to just smash them hard with a shoe. No guts or blood will be splattered. (I have always wondered how is this possible.) If you want to kill a larger mouse just use something larger to smash it with. I can’t guarantee that it will not be messy though. I really found the glue traps more disturbing to use than enclosed snap traps. The mouse struggles and gets stuck to the thick sticky glue until it can’t move. Then you have to approach it laying there helpless and kill it. I used a BB gun but I’d rather just release a dead mouse from a snap trap than deal with all that. ---
**Author:** ![The\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_librarian/32/402_2.png) [@The\_Librarian](https://boards.straightdope.com/u/The_Librarian)\ **Post date:** [March 28, 2012, 1:34pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/79 "2012-03-28T13:34:40Z")
[What’s the most entertaining way to kill mice?](http://www.flickr.com/photos/76671337@N08/7023825711/) ---
**Author:** ![spifflog](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@spifflog](https://boards.straightdope.com/u/spifflog)\ **Post date:** [March 28, 2012, 6:40pm UTC](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481/80 "2012-03-28T18:40:50Z")
> [@Sethcrzygy86](#): > > Seriously, mice are clever. You can only use a trap one or two times, then the mice simply avoid it. This is why poisons work slowly, so the mice don’t associate the food with death. > > Mice quickly learn to avoid glue traps, they don’t go into electronic traps and one a trap is sprung, they won’t go near another one again. As long as there is food or the smell of it, mice don’t care about getting food. They avoid it. This makes no sense. I’ve killed 30 or 40 mice with the same trap. I’ve set five traps within two feet of each other and had five dead mice in the morning. Mice are dumber than a box of rocks. [Previous page](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481.md?page=3) [Next page](https://boards.straightdope.com/t/whats-the-most-humane-way-of-killing-mice/616481.md?page=5)