Breeding: Inheritance and Version Changes
Choose an inheritance target before rearranging the house: an ability, better base stats or a body part. These are different outcomes; improving one does not guarantee the others.
Check the Version First
The developer’s 1.1 notes changed Stimulation’s interaction with inbreeding and parental birth defects, and mutation behavior. The older formulas below are historical references, not unconditional predictions for 1.1 or later.
Their source is SciresM’s reverse-engineering notes, updated before 1.1. This guide does not supply an independently verified replacement formula for later builds.
Older Stimulation Formulas
Let S be room Stimulation; cap probabilities at 100%.
| Historical calculation | Formula | Threshold |
|---|---|---|
| First active inheritance attempt | 0.20 + 0.025 × S | 32 |
| Second active inheritance attempt | 0.02 + 0.005 × S | 196 |
| Passive inheritance attempt | 0.05 + 0.01 × S | 95 |
| Prefer the higher parental stat | (1 + 0.01 × S) / (2 + 0.01 × S) | No finite guarantee |
An inheritance attempt does not promise the exact skill you want, or that a breeding attempt produces a kitten.
Worked Example: Stimulation 20
The historical model gives:
- first active:
0.20 + 0.025 × 20 = 70%; - second active:
0.02 + 0.005 × 20 = 12%; - passive:
0.05 + 0.01 × 20 = 25%.
These are arithmetic examples, not measurements from a current build.
More Stimulation Does Not Mean Perfect Stats
The older stat calculation gives 2 / 3 ≈ 66.7% at Stimulation 100 and 3 / 4 = 75% at 200. Doubling the room’s number does not make either result 100%. A chance for one stat is also not the chance of a perfect kitten.
Selecting parents remains a separate decision from selecting furniture.
Plan Around Your Goal
| Goal | What to inspect first |
|---|---|
| A specific active | Which parent has it and what other skills can be selected |
| A useful passive | The parents’ effect text in Classes |
| Better base stats | The values being inherited, rather than assuming all combat gains pass down |
| A mutation or body part | The installed version, parental defects and inbreeding context |
Compare one change at a time: keep the pair fixed while changing the room, or keep the room fixed while comparing pairs.
Diagnose the Result
No kitten: check parental eligibility and the game’s room/status information. Inheritance percentages are not standalone breeding-success rates.
A different skill: review every candidate skill on the parents. An inheritance attempt and selection of your preferred skill are separate questions.
An unwanted defect: check version and family relationship before reusing old estimates; the 1.1 changes matter here.
Inconsistent results: record the pair, room, game build and outcome. A few attempts cannot establish an exact probability.
Sources and Scope
Reviewed on October 8, 2026. Historical formulas come from the linked reverse-engineering analysis; the version boundary comes from developer notes. The examples are calculations, not gameplay tests.
See Furniture and Cattery for room planning and Combat for deciding which abilities to preserve. The site’s game-data snapshot has no recorded build; verify exact effects in your installed version.