40d:Vermin

Vermin are small creatures such as rats, bats, and lizards which are difficult to see. Most maps have hundreds or thousands of vermin. The presence of vermin can be noted if you are particularly observant, as they will occasionally blink into and out of view on the screen.

Risks

Vermin are primarily notable for their ability to accost dwarves, whether by triggering deeply-buried childhood traumas or just by being annoying. Most dwarves will have thoughts related to a type of vermin they really dislike, and will suffer a significant mood penalty any time they spot the vermin they hate. This mood penalty can render content dwarves unhappy, although the penalty can be offset by otherwise good living conditions.

Vermin will also eat any food in stockpiles they can manage to get a hold on. Food that has been protected in barrels will be immune, but food that is exposed will be nibbled at and will eventually wear out and be destroyed.

Catching vermin

Small animal traps are designed specifically to catch and hold vermin. A catch a live land animal order issued at a kennel tells a trapper to seek out and catch a vermin animal inside one of these traps. The animal will then be brought to an animal stockpile.

Vermin can be tamed by anyone with the animal training labour preference at a kennel. Tame vermin can then be offered for claiming as pets on the z Status screen under the Animals submenu. However, tame vermin will only be claimed by those dwarves who admire those vermin.

Meat group

Stray, untamed vermin that are caught in animal traps are edible, and will be eaten live as exotic cuisine by some people whose preferences swing that way.

People who are starving will also attempt to find and eat vermin, but if they do not have a preference for that vermin as a food type, they will receive a bad thought from doing so. In a fortress with cats, it may be difficult or impossible for the dwarves to find enough vermin to survive starvation, as even a small number of cats are ruthlessly effective at controlling the vermin population.

Eliminating vermin

Cats are chiefly useful for their ability to hunt down and kill vermin. Cats will wander around the fortress killing vermin. As animals do not presently eat, this is done only for sport.^{v0.27.169.33a} This reduces or eliminates the possibility of dwarves receiving bad thoughts for being accosted by vermin—dead vermin do not bother any dwarf—but exposes a risk that a rotting rat or other larger vermin will release a cloud of miasma and upset any dwarves who pass through the cloud.

Another method of controlling vermin is by building animal traps and periodically catching vermin with trappers. The trapped vermin may then be relocated to a cage (so that the trap may be used again). Certain vermin, such as the fire snake, can also be used to make extracts. Vermin may be tamed at a kennel (though are rarely adopted). Occasionally a dwarf will eat vermin in place of "real" food.