# 420,000 Kittens? The Unspayed Cat To Kitten Calculator

No matter how you do the math, there are too many cats/kittens and too few homes. This calculator attempts to (loosely) apply math calculations to scientific principles as they relate to cat reproduction. Taken into consideration are factors such as a high percentage of owned cats are neutered and a small percentage of feral cats are neutered. Also factored in are annual mortality rates as well as post-weaning survival rates of kittens.

At seven years, the calculator shows 2905 kittens at 7 years (versus 420,000) and 49,000 at 10 years. But no rationale person would think that 2905 kittens produced by one cat and her offspring in 7 years is acceptable. Responsible pet owners should spay or neuter their pets.

Factors:

• The average mature cat can have 3 litters with a total of 12 kittens per year; 10.2 surviving kittens of which 4.7 are female
• The average litter size is 4 kittens with 15% loss before reaching weaning age (3.4 kittens per litter)
• Gender ratio per litter averages of males to females is roughly 46.5% female (of 3.4 kittens = 1.8 males and 1.6 females)
• 35% spay ratio allowance for offspring (unscientific factor balancing owned and stray cats)
• 20% annual mortality ratio

Not factored into this equation:

• An immature cat's first litter usually consists of 2 kittens versus 4.
• Unspayed female cats can begin reproducing at 6 months of age and can produce a litter during the same year of birth.
• 30% feral mortality
•  Year Female Cats Minus Died1 (@ 20% mortality) Minus Spayed2(@ 35% spayed) Breeding Female Cats # Kittens Born # Surviving Post Weaning3 Surviving Female Kittens4 Year 1 0 - 0 - 0 1 female cat will have 12 kittens 10 will survive and 5 will be females Year 2 6 - 1 - 2 3 female cats will have 31 kittens 26 will survive and 12 will be females Year 3 15 - 3 - 5 7 female cats will have 79 kittens 67 will survive and 31 will be females Year 4 38 - 8 - 13 17 female cats will have 203 kittens 172 will survive and 80 will be females Year 5 96 - 19 - 34 43 female cats will have 519 kittens 442 will survive and 205 will be females Year 6 247 - 49 - 86 111 female cats will have 1332 kittens 1132 will survive and 527 will be females Year 7 633 - 127 - 222 285 female cats will have 3417 kittens 2905 will survive and 1351 will be females Year 8 1623 - 325 - 568 730 female cats will have 8766 kittens 7451 will survive and 3465 will be females Year 9 4164 - 833 - 1457 1874 female cats will have 22484 kittens 19112 will survive and 8887 will be females Year 10 10680 - 2136 - 3738 4806 female cats will have 57672 kittens 49021 will survive and 22795 will be females 1http://www.animalsandsociety.org/assets/library/199_s15327604jaws07041.pdf 2http://catvet.homestead.com/devon_rex_project_report_1st_year.doc 3http://la.rsmjournals.com/content/4/1/99.full.pdf 4http://www.royalcanin.us/library/catlittersize.aspx