Frozen ratsicles, anyone?

November 8, 2008 7:57 PM

I've been searching Metafilter for humane solutions to our rat problem and, while a couple sound promising (hmmm...so lighter fluid is really ether??), I haven't seen one possibility mentioned: sticking the little bastards in the freezer. I've tried it, and it works great. For some reason, though, my wife isn't too thrilled at the prospect of Brother Rat nestling, even briefly, next to the frozen peas. What do you think?

First of all, before anyone proposes other solutions, let me emphasize "humanely" -- I know they're loathsome little vermin, but then again, so are a lot of CEOs and lame-duck politicians, and I don't want to head down that particular slippery slope. Way I look at it, our rodent brethren are just trying to make a living like the rest of us... plus, I feel a terrible hypocrite snaring them in a trap called "Hav-a-Hart" only to plunge them into the Icy Waters of Slow Death, which is what I had been doing. (It was the process of elimination: can't release them within 5 miles of another habitation or they just become someone else's problem--and I'd have to drive 100 miles round trip to get that far out in the country--plus they've figured out, swear to God, some way to snatch the bait out of spring traps! As for poison, from all indications the use of it just breeds generations of super rats as resistant to Warfarin as the latest strains of staph are to penicillin)

So, lately, I've been spraying them with water, wrapping the cage in several layers of garbage bags, then sticking the whole package in the freezer. Very effective. But as mentioned above, my wife isn't too wild about the idea, so I do what any other loving husband would do: I wait until she's goes off to work at night, then take them out before she gets home.

Anyway -- finally -- here are my questions: How reasonable do you find my wife's objections, and, in your opinion, how "humane" is death by freezing? I've heard that those who came close to it describe it as a fairly peaceful process...

posted by Olden_Bittermann to pets & animals (38 comments total)

The lengthy wait while soaking wet and cold and trapped in a cage seems to be the cruel part.

I snap their little necks. It's all over in less than a second.
posted by jamaro at 8:03 PM on November 8, 2008 [2 favorites]

A good read on the subject.

In my mind I think this is probably as humane as poison but if you are wrapping the cage in garbage bags they are probably suffocating before they are actually freezing to death unless you are giving them air holes or something...
posted by Octoparrot at 8:08 PM on November 8, 2008

A standard rat trap is most humane. instant death. use peanut butter as bait with a couple wraps of thread.
posted by patnok at 8:11 PM on November 8, 2008 [5 favorites]

I can't see why death by freezing would be more humane than many other forms of killing them. In general, the faster the better, for everyone involved.

I suppose in the long term the most humane solution would be to get a terrier, or a ferocious cat, or some other ratting animal and give him the run of the place until the rats learn to seek creature comforts elsewhere.
posted by Hildago at 8:14 PM on November 8, 2008

We did what Hildago said. We couldn't come up with a humane solution and we were thinking of getting a cat anyway, so the presence of mice just sped up the process a bit. I don't think our cat has ever killed any, his presence seems to have done enough.
posted by youcancallmeal at 8:19 PM on November 8, 2008 [1 favorite]

I don't have rats, but I do have mice. If the snap trap catches them without killing them, I throw the trap in a bucket of water. That's a lot quicker than freezing to death.
posted by orange swan at 8:25 PM on November 8, 2008

Seconding the possibility that they are suffocating in the plastic wrapped cage, rather than succumbing to the cold. If so, definitely not humane. And if there are airholes, it is certainly icky to put it in with your foodstuffs, if not outright unsanitary.

If you can't get a ratting animal, use a regular spring rat trap.
posted by Alvy Ampersand at 8:37 PM on November 8, 2008

Freezing them like this isn't humane in any way shape or form. You'd never be allowed to do something similar to lab rats, no ethics committee would touch it with a ten foot pole. A researcher or animal worker caught doing this would lose their job and probably their career.

If you can't bring yourself to learn a humane neck snap (which is actually somewhat difficult to do for a rat) then buy a trap that does it for you. There are ways around the bait stealing problems as patnok has already mentioned. Just stop with the slow, painful death by cold and suffocation *shudder*.
posted by shelleycat at 8:41 PM on November 8, 2008 [2 favorites]

can't release them within 5 miles of another habitation or they just become someone else's problem

So, I've got good news and bad news.

The good news is, you can go ahead release the rats somewhere else.

Because the bad news is, no matter where you can drive, there will already be rats there.

Unless you're literally throwing them through someone's living room window, you will neither be helping nor hurting the situation.

Oh, and by the way...

they've figured out, swear to God, some way to snatch the bait out of spring traps!

That's because you're setting the traps wrong. And bait the traps with peanut butter, which smells awesome to a rat and is not really snatch-able like a hunk of cheese.
posted by Cool Papa Bell at 8:47 PM on November 8, 2008

How reasonable do you find my wife's objections

Very reasonable. You do know that rats are vectors of disease, right? AND YOU ARE PUTTING THEM IN THE FREEZER? Wow. . .just wow.
posted by MLIS at 8:48 PM on November 8, 2008 [5 favorites]

Lighter fluid is probably not ether, by the way, it's naphtha (if liquid) or butane (if gas); these are aliphatic hydrocarbons, more or less CH3-(CH2)n-CH3, maybe with a ring or branch for variety. Ethers go R-O-R'; diethyl ether, the one we refer to as 'ether' and formerly used as anesthetic, is CH3-CH2-O-CH2-CH3.

That is, I wouldn't try to etherize yourself with lighter fluid, it won't end well.
posted by pullayup at 8:54 PM on November 8, 2008

By the way, I find putting them in the freezer perfectly reasonable, at least from a health standpoint (though it does seem cruel). You don't get the black plague straight from the rat, y'know. Just stick them in a plastic bag or something.
posted by pullayup at 8:56 PM on November 8, 2008

I think out of simple respect for your wife you should keep the rats out of the freezer.

I say this as someone whose spouse put a deceased hamster in the freezer just until he could get around to burying it.

Trap, peanut butter, bucket of water if trap doesn't do the trick instantly. Much quicker and more humane than freezing to death. Plus it will save YOUR life.

Because if your wife finds out what you have been doing....
posted by St. Alia of the Bunnies at 8:59 PM on November 8, 2008 [2 favorites]

How reasonable do you find my wife's objections

They're very reasonable.

in your opinion, how "humane" is death by freezing?

Try a little imagination and empathy here. Have you ever been cold? Have you ever been cold as hell? Do you think people who freeze to death don't suffer? There, you have your answer.

I would find it hard to believe you ask this question seriously, but aside from your flippant title and cutesy comments, you seem to think freezing animals to death is a good idea. Amazing.
posted by jayder at 9:00 PM on November 8, 2008 [7 favorites]

I don't know the kindest way to kill a rat (I know I've got mice in my detached garage, cats in my house, and no mice in my house, but I don't know if that applies to rats) but I do know that lighter fluid is NOT ether. It is sure as hell not the same as diethyl ether, which is the traditional anesthetic, neither is it really the same as petroleum ether - although it is more similar to the latter, both are utterly dissimilar to diethyl ether, the latter two are mixtures of hydrocarbons with different properties, and neither of them is a suitable agent for euthanasia. All are highly flammable, incidentally.

Here is a PDF of one perspective of what are considered human methods of euthanasia in laboratory animals. Soaking and freezing are not on the list. To my mind these animals must know they are dying as much as they know anything and I would be surprised if drowning was not faster than freezing. A fully submerged mammal will be dead in minutes, period. Hypothermia is definitely a longer process. I guess I'd have to wonder if the primary benefit is that you don't have to watch them expire.

This is the first thing that came out of the search "humane rat killer." It might work. You could feasibly CO2 gas them at home either with a setup where you pump it into some kind of jury-rigged container from something like a homebrewing carbonation tank or with dry ice. If I had to routinely kill small mammals without special equipment in my home I suspect I would reluctantly opt for drowning.
posted by nanojath at 9:02 PM on November 8, 2008

Lighter fluid is not ether. You are thinking of starting fluid which used to be made with ether but is now mixed with other hydrocarbons to keep people from huffing it.

The freezer is a terrible idea. The quickest method is the neck snap, and that is considered the most humane. I have also heard that some labs dispose of their rats by placing them in a bucket that has CO2 in it. The CO2 displaces the air and the animals suffocate fairly quickly. You can get CO2 from the right kind of fire extinguisher.
posted by kuujjuarapik at 9:07 PM on November 8, 2008

Yeah, the freezer is mean and kind of gross. Put them in a bucket under the exhaust of your car and run it for a few minutes, the carbon monoxide will build up and kill them pretty fast and humanely.
posted by crabintheocean at 9:11 PM on November 8, 2008

I've killed no rats, but plenty of mice in my day. Ick. No, I wouldn't want them in the freezer either, and no, I don't think slowly freezing to death is particularly humane, although it probably eases your conscience to reduce your direct involvement.

If I ever get a live mouse, well, I pick up the trap with a pliers and drown them in the toilet before I give them their traditional burial at sea. Yes, they thrash, but it's pretty fast, and they were already suffering.

Wait. I do remember a rat somehow appeared in a tenant's toilet (it probably came in through a roof vent -- they can swim hundreds of feet). It was very alive but unable to get a grip on the wall of the toilet. I slammed the toilet seat cover down and flushed repeatedly until I didn't hear a rat anymore.

I have been crawled on by a very intelligent and well-behaved pet rat (having had a ferret I wasn't fazed by it). But the undomesticated ones, well, it is a them or us public health thing. Swallow your moral lumps and get it done.
posted by dhartung at 9:41 PM on November 8, 2008

You'll have to google this on your own but I have heard about rodents having a serious aversion to the smell of cat urine. Just having a cat in the house may reduce or eliminate your problem not to mention the fact that the cat will probably do your dirty work for you.
posted by Octoparrot at 10:33 PM on November 8, 2008

This whole death-by-freezing thing sounds disturbing and torturesque. While I appreciate the sentiment and effort to be humane, frankly, I'm kind of appalled.

Get some regular spring-type rat traps, if trap-and-release is not an option. In my (admittedly limited) experience with them, they seem to result in instant rat death. That seems like a significantly better way to go than several hours of terror involving slow death by suffocation or freezing.

I think you need to put a lot more thought into the speed with which you're dispatching the rats, not just the physical pain involved; I can only imagine that every minute they're kept alive in some foreign place, confronted by strange creatures, trapped, is — in itself — torture. If you're going to kill them, kill them, don't drag it out.

In addition to the old-fashioned coil-spring rat traps (a friend calls them "Looney Toons"-style traps), there are also ones like this which I think are designed to be more universally fatal: the rat can only approach the bait by sticking their head through the hole, so it's less likely to hit in a non-fatal location.

Thought: you could probably increase the fatality percentage on the standard traps by placing some sort of barrier down each side, so that the rat had to approach the bait from the 'short side' (bottom?) of the trap, where the kill bar will have the strongest impact, rather than from the side, where the bar might not kill, or might just get a piece of them.

I've been told that in laboratories where rats must be routinely killed for research purposes, a small guillotine is used. This is an option, although it would require you to handle the rat, which might arguably be worse (in terms of terror factor) than simply using a fatal trap.

I see also from a quick search that there are now electric traps that claim to be the rat equivalent of Old Sparky; these (like the electric chair itself) seem to be more about creating the appearance of a quick, clean death than actually delivering it.

As an aside, the only time I've been faced with this predicament was in dealing with wounded animals (squirrels and smaller) dragged in and left by cats; I've just taken them outside and finished the job with a handgun (22LR). Be difficult with a rat that wasn't already half-dead, though.
posted by Kadin2048 at 10:52 PM on November 8, 2008 [1 favorite]

I'm appalling myself a little by even replying to this, but since freezing the rats to death (and in the freezer where you keep your food) sounds so horrendous, I'm going to second the person who suggested snapping their necks. When I was little, I took a kid's class on reptiles and the leader fed a mouse to a snake, but killed the mouse first by holding it by its tail and whipping its head against the table, or side of the tank (to snap the neck, not stun it). I wouldn't recommend you hold a feral rodent that way, but there has to be some kind of technique with pliers or something. Maybe ask your local pet store (probably not a PetCo, but something more mom-and-pop) what they recommend--they probably sell mice to other snake owners that would rather not see the entire gruesome natural act played out at feeding time.
posted by tyrantkitty at 10:53 PM on November 8, 2008

We use the Rat Zapper. It's a little tunnel with an floor that becomes electrified when the rat puts his weight on it. You can put a little bit of bait in the tunnel, but you may not need to. Rats seem to have an instinct that tells them to explore tunnels.

Rat Zappers are about as humane as a rat trap can be. One zap and the rodents are dead.

Make sure you read the reviews on Amazon. Zappers have worked for us, but they don't work for everyone. Rats are smart, and some rats are smarter than others. I've also found that Zappers are cheaply made. They work well for a while and then they break. So I buy a new one every four years or so (which seems to about coincide with our rodent-infestation rate).

Note: we've only ever had mice, never rats. But the product has worked well, and it IS called the "Rat Zapper."
posted by grumblebee at 11:05 PM on November 8, 2008

I think it's also worth pointing out that simulated drowning (actually not even drowning, just being in a pool of water without anything to stand on) is used in research labs as a way to induce terror and "stress" in rats. (Memory studies use pools with submerged platforms pretty extensively, and I've personally seen trials where a rat was placed in a pool where the platform had been moved; you better believe that rat was "stressed.")

Nothing involving drowning is even remotely humane, by any reasonable definition that I can imagine. Arguing whether drowning is more or less humane than Warfarin poisoning seems a little like debating the relative merits of waterboarding versus the rack: once you get past a certain point, to where you're clearly causing mortal terror either way, isn't the difference a bit academic? It reeks of justification.

Drowning animals seems to be historically popular because it's "hands off" and doesn't require much effort or make much mess — it's not doing the animal being killed any favors.
posted by Kadin2048 at 11:22 PM on November 8, 2008 [3 favorites]

Agreeing that faster is better. I imagine it would take at least an hour or two of suffering before they died.

I personally trap and release in a park about a mile away. Or invite the feral cats to hang out under the house for awhile.

(also, isn't waterboarding considered torture because it gives the sensation of drowning?)
posted by Vaike at 11:48 PM on November 8, 2008

Nothing short of putting it into a deep sleep from which it does not awake would be a pleasant way for a rat to die, and there is no commercially available product like that.

You need to become heartless in this or you will lose to the rats. Don't use poison or you'll be introducing unnecessary nasty chemicals into the environment, and poison is slow and may allow the rat to die somewhere unreachable but quite smellable. Drowning and freezing are also slow and painful. A fast mechanical or electrical trap will cause them very brief pain and fear, and then it will be over.

If you have property and a post-hole digger or a good thin shovel, you could bury 'em deep and safe. Return them to nature. Otherwise, you've got a flea-infested carcass to bag and trash. Don't touch it.
posted by pracowity at 12:24 AM on November 9, 2008

Best case scenario is to have them avoid the place entirely.

Maybe you're not in a position to get a terrier or a cat. A twenty year pet committment is a big investment just to be rid of rats! Offer to look after a friend's pet while they're at work. Or stick a small ad in the local paper offering your services as a dog-sitter. You'll scare off the rats and make some cash on the side!
posted by the latin mouse at 2:16 AM on November 9, 2008

*shudder*

As god is my witness, if I knew that my husband had put a wild rat in my freezer to slowly suffocate and then congeal, I would have to have a new freezer. And maybe a new husband. Good lord, what are you thinking?

There are many solutions here that work. Electric traps, terriers, a giant boa constrictor...but for the love of all things cold and yummy, never put another rat in the freezer.
posted by dejah420 at 2:19 AM on November 9, 2008 [3 favorites]

Vermin. Stomp it. Less cruel than death by cat.
posted by alex_reno at 3:36 AM on November 9, 2008

I had a serious rat problem a few years ago, and it was because they were attracted to the bird seed I was putting out for all the cute little birds. I quit keeping score after I had caught over fifty rats in three spring traps. I had also been putting dry cat food out for the crows, but I found that the crows would eat the dead rats.

The crows had little difficulty tearing open the juveniles but the hides of the adult rats were a lot tougher, so I would cut them open with a sharp knife. The rats just kept coming and the situation had become seriously bizarre (I gave the spring traps names, and cut a notch for each kill along the edges)--

Finally I stopped buying bird seed. The rats went away. What is it that attracts the rats to your place?
posted by Restless Day at 3:59 AM on November 9, 2008

You need to make sure your property is less enticing to rats. Clear up all and any garbage thoroughly, make sure your bins are sealed and any spills around the bins are cleaned up. Keep the kitchen floor free of food debris. Restless Day's point about bird seed is good too.

Seconding Shelleycat's suggestion. If you must kill them, then it needs to be as quick and clean as possible. Your experiments with freezers, water, plastic bags and lighter fuel (wtf!) sound utterly inhumane.

..and btw, getting a cat is no guarantee of clearing your rat problem. Not all cats are hunters and not all cats who are hunters are successful hunters. Nor are they machines to do your bidding.

The most humane way of dealing with this is to prevent the problem in the first place.
posted by Arqa at 5:59 AM on November 9, 2008

I agree with Arqa, in that the best solution is to prevent the infestation. The woman who previously owned my house had a rat problem, because she failed to cover the drainage hole in the basement that led directly to the sewer. Hole covered = problem solved.

From a pest control website:

If rats are getting into a building it is essential that the entry points are located and filled (you may need a builder for this) or the problem will repeat in the future. If you do not wish rats to return then you must address the reasons as to why you had rats in the first place. Rats need three things in life to thrive: food, water and cover. Gardens will often include all three and any attempt to eliminate infestations and keep from being re infested will fail unless these three problems are addressed. The main culprit is bird feeding as this supplies rats with a high energy food at regular intervals in a fixed location. Birds are messy feeders and small amounts of nuts pecked off a feeder will support a population of rats which will breed all year round and then push out its young to the surrounding area to start new colony's. Bird feeding can damage wildlife by increasing the amount of rats, mice & grey squirrels in an area to an artificially high number which all can be harmful to the natural wildlife population. Many people die each year after catching diseases carried by rats & mice. Compost heaps often provide a warm place to live in the winter with a regular supply of food if used at regular intervals. Rats are also attracted to the smell of rubbish (bins) and any other animals. This includes predator animals such as dogs. The reason for this is that in the wild rats would eat left over food & droppings from wolves, foxes & other animals. The same applies to chickens, rabbits & guinea pigs. So if you have pets clear up droppings, check that their food is stored in a rat proof container, that litter & droppings are not put on compost heaps & that hutches & runs are rat proof.
posted by bolognius maximus at 6:47 AM on November 9, 2008

The wooden snap traps that look like ordinary mouse traps, just bigger, don't work worth a damn. What you need are the black plastic snap traps; you can get them at the hardware store. I'm also going to second the Rat Zapper mentioned above. With either the plastic traps or the Zapper, the rats are dead by the time you find them, which is, of course, the ideal situation. Rats are unbelievably horrible; just try to kill them as quickly as possible. Or move - I, personally, moved.
posted by mygothlaundry at 8:25 AM on November 9, 2008

What you need are the black plastic snap traps; you can get them at the hardware store.

MGL and I suffered rat infestations at about the same time, I think. The exterminator I hired used those black snap traps in the crawlspace where my HVAC ducts are. The first few times, they worked perfectly. Six months later, either because of repeated use or because of the evolution of the rats' skills, they worked less well. One rat took 3-1/2 days to die. The one that got caught last week took about 30 minutes.

Maybe they need WD-40 every once in a while or something, or maybe the rats are getting more tentative, but they seem to get less effective over time. Just a data point, since we're talking about reducing suffering here.

Also repeating what others have said above -- exclusion is the key. Find out how they're getting in. Check your roof, especially. I had several vents up there that weren't screened off at all. (Stove vents, sewer vents, a fan port for an old swamp cooler, etc.) Cover all openings with 1/4" hardware cloth, and make sure the hardware cloth is secured with screws + washers.

The rats are going to be around, regardless. In my case, my next-door neighbor has about 20 bird feeders, and there are fruit/nut trees everywhere. Around here, I'll never get rid of the rats, so I've got to focus on keeping them out of the house. (And by god, I'm going to win. Do you hear me fuckers? I'M GOING TO WIN.)
posted by mudpuppie at 10:21 AM on November 9, 2008 [1 favorite]

Rat traps are highly effective. But it's possible to make them even more user-friendly. After the spring-loaded bar is cocked, you may still need to pick it up and move it to its final location. If your finger happens to be holding the sides where the bar would come down, and the bar accidentally snaps shut, you're in for a world of hurt.

Another problem with the design of the conventional Victor brand rat trap is simple Newtonian physics. the same force that rotates the bar onto the rat "wants" to rotate the whole trap in the opposite direction. The Victor base plate appears to be made of pine, or some other soft wood, and thus has a low inertia to resist this acceleration.

On at least one occasion, I had a trap sprung, with no vermin inside. In this case, the entire trap had done a back flip, so I came to the conclusion that rat escaped death due to the trap moving while the bar came down.

To solve both of these problems at once, I glued an over sized wood board to the underside of the Venerable Victor. If the bar accidentally shuts while I'm positioning it, it won't hit my fingers, as I'm holding the contraption by the new base-board.

To further enhance the effectiveness of the Victor, one can polish the "sear" of the trap. This is the interface of the trigger bar and the "bait pan". Using pneumatic rotary tools and a fine Roloc disk, I mirror polished the part of the trigger bar that contacts the bait pan, thus lowering the lateral force required to actuate the trap.

I should like to take this opportunity to boast that these enhancements have enabled me on two occasions to catch mice with an "enhanced" Victor rat trap.

On one occasion, my best efforts came up short. I suspect that the rat inserted its tail onto the bait pad before its head. Thus I was faced with your conundrum, what to do with a live rodent caught in a trap, this one by its tail.

The beast was positioned on top of a pile of soft attic insulation, thus a conventional truncheon blow may have only pushed it deeper into the cushioning. If the first blow did not dispatch, it might have enough force to dislodge its tail from the trap.

Plan B was the use of the Ruger .22 pistol, but not with a conventional round. An ideal round for indoor vermin termination is the .22 CB. No need for ear plugs, and it won't wake up the neighbors. Not even as loud as a firecracker. Vermin death was nearly instantaneous.

I find the "death by slow freezing" to be barbaric, and beneath the dignity of the genteel culture of Metafilter...
posted by Tube at 10:37 AM on November 9, 2008 [3 favorites]

A couple thoughts:

Don't learn cervical dislocation as a killing method (snapping necks). This is a procedure meant for lab animals, which have been grown in a germ-free environment, and thus their feces and body tissue have no communicable diseases. Your rats, on the other hand, could be covered in all kinds of awful disease that you don't know about. Thus, do not expose yourself to the possibly pathogenic rats!

Also, don't put them where you store your food. Also bad. CO2 is good, but they can wake up later, even if they look dead, especially if you have a really limited amount of CO2, as in the case of a fire extinguisher. My boss at work told me this once happened to him as he was dissecting a rat. He gassed it, took it to the bench, and started cutting it's skin open, when in woke up. He told me it looked like the rat was trying to run away, but could only use half of his body. He ended up having to grab it by the tail and smack it on the bench to kill it. To avoid this scenario, you can subsequently use cervical dislocation after gassing the little bastards, but once again, you have to touch them - hell no!

Thus, I'd go with the electric trap. You don't touch the plague-ridden furballs, and it guarantees a fast death - certainly less painful than the hypothermia you have already been subjecting them to.
posted by wuzandfuzz at 1:13 PM on November 9, 2008

I went through this exact problem. My kids didn't want to "kill" the suckers. We went to Plan B. It took some experimentation but worked. We went over to Home Depot and picked up about 18 of those sonic devices that supposedly drive rats nuts. There was a lot of speculation on these devices all over the net. I decided that if we did sonic Armageddon it might work. So, along with the 18 devices we also purchased one of the "mega" models. A small black box that lets out a screeching type sound.
We went on a week long vacation but before we left we plugged in each of the devices through out the house and put the mega model on full blast in the attic where we suspected was where they were entering from. Secretly, I also left out three classic traps to see what they might net.
We returned from vacation and all of the bastards were gone. No droppings, none of our food was chewed into and there were no dead bodies in the classic traps. It seemed to of worked. I followed up by unplugging each of the devices and turning off the mega machine.
Now, we fire up the devices about once a month for a night (except for the big one), then turn them off. This has seemed to of worked wonders for us... and, as always, YMMV!
posted by bkeene12 at 8:00 PM on November 9, 2008 [1 favorite]

Seconding the sonic device, and adding Norwegian Forest Cats. A few years ago, we lived in an area that had quite an abundant vole/mouse population. Our Norwegian Forest Cat patrolled the acreage daily, and within a couple of months, there was nary a rodent remaining on the grounds. The drawback with hiring felines for the job is that they may bring home an occasional trophy or two as proof of their efficacy.
posted by terranova at 10:23 PM on November 9, 2008

Keep in mind that to humanely kill a rat using anesthetic or CO₂ you need to be trained. It's not as easy as just putting the rat in with some gas and waiting for it to die, there's a technique to the whole thing without which the animal panics and dies badly. Same goes for using a guillotine, you need to have the rat properly restrained and stuff (not sure of the details). So for the layperson those are not suitable as humane killing methods.

Even cervical dislocation really should be taught as there is a bit more to it than just a snap (by the way, I expect you're wearing gloves for all this right?). However it's likely the easiest to master and will kill the animal instantly (two ways at once if done correctly) and, more importantly, if you have the right trap that will do it for you. So read the above advice about traps, get the correct ones and ignore all the stuff about gassing or freezing or drowing.
posted by shelleycat at 6:13 PM on November 10, 2008