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How Cities Are Using Dry Ice To Kill Rats (usatoday.com)

Some of the United States' biggest cities have resorted to using dry ice to kill rats. Since dry ice (frozen carbon dioxide) turns into a gas, sanitation officials simply need to drop chunks of it into rat infested burrows and let science do the rest. Longtime Slashdot reader mi writes: USA Today reports: "Earlier this week, USA TODAY observed Chicago sanitation department workers at one of the city's oldest parks scoop chunks of smoking dry ice into a burrow before quickly covering the entry and exit holes with dirt and newspaper to stop any rats from escaping as the -109.3-degree Fahrenheit gas dissipated. Sanitation workers say they treat burrows during morning hours, when rats are less active and most likely to be huddled inside the burrows. The asphyxiated dead rats then decompose in place and out-of-sight of city denizens who count the disease-carrying vermin among the vilest of indignities of urban living. 'We are seeing 60% fewer burrows in areas where we are using the dry ice,' said Charles Williams, Chicago's streets and sanitation commissioner. 'It's more environmentally friendly, and it's very humane on the rodents as well.'" Humane or not, what is so especially "undignified" about rats? What makes them worse, than, for example, cats, deer or wild horses?

11 of 429 comments (clear)

  1. Very cruel by Anonymous Coward · · Score: 1, Interesting

    I have pet rats and I think this is extremely cruel. Rats are highly intelligent and make super companions to humans - equally as affectionate as dogs in every way, and yes, you can train rats in much the same way.

    1. Re:Very cruel by sjames · · Score: 3, Interesting

      There are better ways. When I had some yellow jackets move in, I blasted their nesting area with cinnamon powder. Apparently, they like the smell about as much as humans like a garbage dump.

      As for termites, yeah, sometimes you have to resort to poison. It's about a measured response, not no response.

    2. Re:Very cruel by Immerman · · Score: 5, Interesting

      House centipedes. The grey-brown kind with lots of long thin legs.

      They're completely harmless to humans, even kinda cute for a bug, and are voracious predators against virtually all the home-infesting insects that we dislike, including termites, cockroaches and nigh-indestructible bedbugs. They can even become kind of friendly as they mature through their seven-year lifespan, if you're into befriending your "guard dogs".

      I'm not above squishing particularly annoying bugs, but fostering a population of human-benign predators is far more effective, and controls potential infestations long before you even notice you've been invaded.

      --
      --- Most topics have many sides worth arguing, allow me to take one opposite you.
  2. Re:Not a nice way to die by dbIII · · Score: 3, Interesting

    But, yeah, they're rats.

    The normal way is to make them eat a lot of warfarin until internal bleeding kills them.

    If you want to kill stuff than is not neatly lined up in the stockyards it's generally going to be messy and horrible.

  3. Rats are very clean animals. by tlambert · · Score: 5, Interesting

    Rats are very clean animals.

    Except, you know, for:

    lymphocytic choriomeningitis
    bubonic plague
    typhus
    hantavirus
    leptospirosis
    rat-bite fever (it's a real thing; look it up)
    salmonellosis
    Colorado tick fever
    cutaneous leishmaniasis ...but except for those, VERY CLEAN!

    1. Re:Rats are very clean animals. by Ungrounded+Lightning · · Score: 3, Interesting

      Rats are very clean animals. Except, you know, for: ...

      They're also very friendly and cuddly. They tend to get into cribs with human infants and treat them like fellow rats: Cuddle up, clean their ears, etc.

      Unfortunately, rats react to a dead rat in the burrow by eating it. Humans, when they first fall asleep, tend to be in a deep sleep for something like 25ish minutes, from which it is very hard to rouse them - even by a rat bite. 25ish minutes is long enough for rats to decide a baby or child might be dead, test it by nibbling, then start chewing...

      --
      Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
  4. Re:Not a nice way to die by Anonymous Coward · · Score: 0, Interesting

    Nitrogen is WAY more humane.

    I once had groundhogs in my garden. Dumped a quart of ammonia down the hole and covered it. Excess ammonia became fertilizer (so did the groundhog).

  5. Re:Definitely not humane by Anonymous Coward · · Score: 3, Interesting

    It's not quite that simple. What works will for pigs does not work well for all animals. I use a number of animal models, including mice and rats, in research studies. CO2 asphyxiation is the currently preferred method for mice and rats for humane euthanasia, provided the exposure concentration is kept low. Argon has been shown to induce aversion in rats (as an indicator of pain), while N2 exposure has had mixed results in varied studies. It's possible N2 is more humane, if the mix was correct, but that is far from clear to me, and I am roughly familiar with current best practices and research (yes, there is research on the most humane way to kill animals).

    Of course, what is done in a controlled lab environment is distinct from dropping a brick of CO2 into a warren. Extremely high concentrations (>40% or so if I recall correctly) of CO2 can induce burning sensation, while lower concentrations induce unconsciousness without apparent aversion in rodents. I'm really not clear on exactly it would happen in an uncontrolled environment, but it is far from clear to me the N2 would be a better option.

  6. Think of the contractors by AHuxley · · Score: 1, Interesting

    Why is big government doing the job of the private sector?
    Who invested in vans, trucks, equipment and had to tender, bid for rat control work.
    Governments that set standards are using cheap science to alter the natural balance of capitalism.
    Think of the chemical sales, support jobs, local businesses that are all working to keep trucks stocked and chemicals flowing with the long term aim to stabilise rat populations.
    A large self supporting rat population can provide decades of control work, with very few of the larger rats noticed out during the day.
    If the rat populations are allowed to drop so dramatically in one generation thanks to big gov meddling, think of the local jobs lost.

    --
    Domestic spying is now "Benign Information Gathering"
  7. Re:Not a nice way to die by Chas · · Score: 3, Interesting

    Honestly, dry ice is probably a LOT more humane than rat poison.

    The whole reason rat poison functions is because rats don't have a gag reflex. Once they "acquire" something by eating it, the only way to get rid of it is via full digestion and pooping it out.
    So they can't puke up rat poison. This gives the toxin plenty of time to kill the rat, especially with their high burning metabolism.

    Dry ice evaporates into CO2 and knocks the rats out. Then, as the CO2 levels climb, kills them.

    If you've ever seen the "Crazy Russian Hacker" video where he builds a work bucket-based "air conditioner" and uses dry ice instead of regular ice? DUMB.

    This explains it in excruciating detail. https://youtu.be/YIgV2Q8Leh0

    --


    Chas - The one, the only.
    THANK GOD!!!
  8. Re:Not a nice way to die by AK+Marc · · Score: 3, Interesting

    Just a few EMPs, and their kill-bots to wipe up the confused meatsacks left behind. No nukes, that'd spoil their conquest. Unless they mastered anti-matter bombs. Though radioactive, the radiation from those is quite short lived.

    Though, I want to see the aliens with an orbital drill. Drill to the core, heat it up 10,000 degrees, watch the continents melt, while they reform the planet in our image. When the construction workers make a house, they don't exterminate the ants first. They leave that to the bulldozers.