Cat Drop | Hacker News Reader

Cat Drop

en.wikipedia.org

42 pointsstcredzero14 comments

Followed closely by a dog drop in 1963: https://en.wikipedia.org/wiki/There_Was_an_Old_Lady_Who_Swal...

Funny you mention that. I was wondering how effective cats are at controlling rats. I would have suggested a rat terrier drop.

A talking rat character in a fantasy book I'm reading points out the illogic of a boat taking on a cat to catch a single rat. The cat is likely to eat more food than the rat. I wonder if rat terriers would be more efficient?

>catch a single rat.

There's rarely a single rat

True. It was the case in the book, but that's fiction.

It’s raining cats and dogs :P

> In several of these cases, the cat fatalities were the result of cats licking their fur after brushing up against a wall or other surface sprayed with DDT.

This is, of course, reminiscent of the legendary Dwarf Fortress issue where cats would die of alcohol poisoning after walking on a tavern floor and licking their fur contaminated by spilled booze… There was nothing wrong with this unexpected emergent interplay of features per se, the only actual bug was that one "unit" of contaminant was unintentionally treated the same as a whole serving of alcohol, a lethal amount to a cat-sized creature!

My favorite "unintended consequences" story is the story about the Cobra Effect[1]. To me they're very closely linked not because one creates circumstances using incentives and capital, but because people fail to see consequences several steps ahead.

1. https://en.wikipedia.org/wiki/Perverse_incentive

I was thinking, "truth was probably closer to 30 cats than 14,000", until I looked up Borneo in wikipedia. It has over 280,000 square miles, so 14,000 cats works out to a little over 20 square miles per cat. So, I could believe that they needed something like 14,000 cats to make any difference.

By the way, where I live in southeast Austin, Texas, USA, I have seen feral cats catch rats on many occasions. So, for those who think feral cats catching rats is not a real thing, believe me, it totally is. Most of the time it probably happens at night, and I'm not outside that often even during the day, so if I've witnessed it on multiple occasions it must not be very rare.

I think WHO indiscriminately spraying DDT is bigger news. It's what killed the original cats in the first place, and how much damage did it do to humans? It was a different time...

>I think WHO indiscriminately spraying DDT is bigger news.

When DDT was first introduced they did studies on cats, humans, dogs. It can kill a cat, but the dose needs to be extremely high, reported as 300mg/kg. (one of the sources on it: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2057789/pdf/brm... )

You'll note the article mentioned dieldrin was used briefly. Less than 25mg/kg is enough to kill a cat: https://www.sciencedirect.com/science/article/abs/pii/004100... . It also bioaccumulates and is extremely persistent.

DDT was sprayed consistently because it was known to be fairly safe for mammals, cats have a shit liver for breaking down most pesticides but I still think the dieldrin is the real culprit here since there's documentation of its use and it's way nastier to mammals.

EDIT: Yeah, consistent with what I was thinking, I looked for measurements of the various pesticide residues in the environment around Malaysia: https://enviro2.doe.gov.my/ekmc/wp-content/uploads/2016/08/1... (spoiler: aldrin and dieldrin were often found in higher concentrations than DDT and as mentioned before have much greater toxicity)

It's not about killing a human but causing other issues. Xenoestrogens accumulate and as you eat something that grew up around it you accumulate some of that too. For older people it may be fine but at younger ages they wreak havoc, accelerate sexual development but at the same time cause fertility issues like reduced sperm counts (https://en.wikipedia.org/wiki/Xenoestrogen#Mechanism_of_acti...).

Sure at the time some of these studies maybe were unknown but I think it's always worth asking yourself if you spray some new chemical that you know is great at killing some harmful wildlife around people in a faraway country, will it also harm people in that country for generations.

It's still acceptable to use DDT as an insecticide for malaria control (in areas where mosquitos are not DDT resistant). There are certainly negative effects on other wildlife and humans from that use, but specifically on humans, I think there's a risk/benefit analysis that at a population level, reduced malaria outweights negatives from DDT exposure.

It's probably helpful to use targetted spraying rather than indiscriminate spraying, but DDT is a powerful insecticide and it's going to have broad effects on wherever it's sprayed.

The notion that toxins accumulate in greater concentrations the farther up you go in the food chain, eventually ending up in apex predators like cats, eagles, and so on; seems to have not been well understood at the time.

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