Catplosions (Tarn loves cats, cats reproduce, too many cats kills DF performance)
This was a particularly insidious one because the usual strategy of culling excess livestock doesn't work out when applied to dwarfs' pets (pets can't be designated for slaughter, and other means of making pets die will make their owners upset). With most animals, you can avoid the pet adoption issue by just not marking them as available for adoption, so you wouldn't have to worry about a dogsplosion, sheepsplosion, etc. Cats do not become pets through that system. Instead, a cat adopts a dwarf.
Note that the obvious strategy of not having any cats at all doesn't work well because cats are the most/only easily-available HUNTS_VERMIN creature, so you need some around to protect your food stockpiles.
A somewhat effective solution is to use male cats for stockpile protection, and keep female cats caged (which IIRC stops both adoption and breeding) and only let one out at time (cage any resulting (female) kittens immediately). There's not (yet) any simulation of evolutionary pressure to adopt a owner quickly, so you can just prefer kittens that do so for the next breeder when the current one dies of old age.
Gelding (neutering) the male cats also works, but is less sustainable if you don't have a reliable source of replacement cats from migrants or trade caravans for when the current ones die of old age. Spaying is not supported AFAIK.
You can also just remove the ADOPTS_OWNER token via raws editing.
I. M.> John, the kind of control you're attempting simply is… it's not possible. If there is one thing the history of evolution has taught us it's that life will not be contained. Life breaks free, it expands to new territories and crashes through barriers, painfully, maybe even dangerously, but, uh… well, there it is.
H. W.> You're implying that a group composed entirely of female animals will… breed?
I. M.> No. I'm, I'm simply saying that life, uh… finds a way.
Verily, the dwarf would pick up a cat to take it to the slaughterhouse, the cat would adopt the nearest dwarf (the one carrying it) and then the dwarf would slaughter the cat.
And get sad because his pet died. And then eventually start tantruming and a tantrum spiral would begin.
It's so crazy when you try to make dwarves feel great all the time and then the simulation comes up with some completely insane causal chain that messes up everything.
I once tried to isolate a miasma problem with a wall. Which works fine, unless the dwarf tasked with building the wall decides he needs a break, sleeps on the floor and then gets grumpy because he just slept on a hard surface in a smelly area.
This is why I always spent an inordinate amount of effort on my dining hall - get that thing fancy enough and the dwarves could endure quite a bit before they flipped.
This was a particularly insidious one because the usual strategy of culling excess livestock doesn't work out when applied to dwarfs' pets (pets can't be designated for slaughter, and other means of making pets die will make their owners upset). With most animals, you can avoid the pet adoption issue by just not marking them as available for adoption, so you wouldn't have to worry about a dogsplosion, sheepsplosion, etc. Cats do not become pets through that system. Instead, a cat adopts a dwarf.