Probably Stolen Rats: Mouse Trap, Breeding & Rat Stats
Bait a Mouse Trap with Processed Cheese for a 50% nightly catch chance (1% without bait). Keep rats in a cage under 55% crowding with a Livestock Feed Dispenser, breed them from age 3, and butcher heavy adults: a 400 g cut is worth 159 base Credits. Never feed rats rat meat — it spreads prions.
On this page
How to catch rats with a Mouse Trap
| Trap setup | Result |
|---|---|
| Empty trap | 1% catch chance per night |
| Baited with Processed Cheese | 50% catch chance per night |
| Cheese use | Eaten on a catch; 25% chance to be lost on a miss (about 62.5% used overall) |
| Caught rat | 50/50 male or female, aged 3–7 |
| Occupied trap | Does not catch again until emptied |
If you start as the Rat Wrangler you skip this step: the run begins with a cage, a feeder and three males plus three females aged 5, 3 and 1.
Cages, crowding and escapes
A cage starts at 10 × 3 with 100 health and can be expanded with Metal Ingots up to 10 × 8; each extra row adds 20 health. Every night it loses health equal to living animal cells ÷ 4 (rounded down). Repair it with Scrap Metal, which restores half its maximum.
Below 20 cage health, rats can escape whenever they move. Keep it above 20.
| Crowding (occupied ÷ area) | Effect |
|---|---|
| Up to 55% | None |
| Over 55% (level 1) | Fertility −20%, more infection risk |
| Over 70% (level 2) | Fertility −40%; 5% chance a rat kills the lightest smaller animal |
| Over 90% (level 3) | Fertility −60%; 15% kill chance |
Feeding and growth
A rat has 500 maximum hunger and uses 65 per night. It looks for food below 75% (375), so a Livestock Feed Dispenser set to the default 85% target tops it up to 425. Rats will not eat loose fish feed, sewage pellets or cans.
Young rats gain 75 g per night, adults aged 5–10 about 17 g, and rats aged 11–13 start losing weight — butcher before age 11. A rat that is still at 0 hunger on the next check dies.
Rat stats and genetics
Each pup takes one allele from each parent with a 15% mutation chance per allele, so selective breeding works. A Gene Scanner (500 Credits) shows true genetics; Red and Green Serum boosts are not inherited.
| Stat | Baseline | What it does |
|---|---|---|
| Growth | 1 | Multiplies nightly weight gain |
| Hunger | 65 | Food used per night |
| Fertility | 50 | Percent chance to conceive per pairing |
| Litter | 3 | Average pups (2–4 at 3) |
| Immunity | 30 | Disease resistance; below 25 health drains |
| Max health | 100 | Health pool |
| Longevity | 1 | Delays old age and the age-11 fertility drop |
Breeding checklist
- 01
Pair mature rats
Both must be at least 3, alive, not pregnant, not neutered and not starving.
- 02
Keep them fed above 200 hunger
Low hunger, disease (×0.75) and crowding all cut fertility.
- 03
Wait three checks
Pregnancy lasts 3 checks. A starving mother has a 75% miscarriage chance each check.
- 04
Make room for the litter
Newborns start at 25% hunger and need space — crowding over 55% starts hurting the colony.
Butchering and rat meat value
Body weight is split into the largest cuts first, so a 450 g rat gives 400 g + 50 g. Diseased rats count at 75% weight. Heavy rats are worth more per gram — the 400 g cut is about 20 Credits per 50 g against 15 for small cuts.
The Auto Butcher (400 Credits) can do this overnight; mark breeders with a Marking Pen to protect them.
| Cut | Base value |
|---|---|
| 400 g | 159 Credits |
| 200 g | 65 Credits |
| 100 g | 30 Credits |
| 50 g | 15 Credits |
Feces, disease and prions
Rats that gain 30 g or more in a night leave Animal Feces. Once feces and carcasses cover 25% of the cage, infection rolls begin. A Cleaner Robot (250 Credits) collects feces every night without power.
Feeding rats rat meat risks prions (−20% growth, immunity and longevity) that pass on to the meat. Known prion meat always infects.
Common questions
How does the mousetrap work in Probably Stolen?
Place it overnight. Empty it has a 1% catch chance; baited with Processed Cheese it has 50%. A full trap will not catch another rat until emptied.
How much is rat meat worth?
Base values are 159 for a 400 g cut, 65 for 200 g, 30 for 100 g and 15 for 50 g. Sale price still depends on the buyer and display case.
When should I butcher a rat?
Before age 11, when rats start losing weight. Heavier rats yield more valuable large cuts.
Why are my rats not breeding?
Check they are 3 or older, fed above 200 hunger, healthy and not crowded over 55%.
Sources & version notes
Community game-data research. Sources reviewed October 31, 2026. This guide does not claim an independent in-game test.
- Nico Wiki: rat ranching
Trap chances, cage, crowding, hunger, growth, genetics, breeding, butchering and prions.
- Nico Wiki: Rat Wrangler occupation
Starting kit and meat cut values.
- Nico Wiki: growing & ranching
Auto Butcher, Cleaner Robot and Marking Pen.