# 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

• "; echo ""; //each cat will have 4.7 female kittens for (\$i = 1; \$i <= 11000; \$i += (\$i * 4.7)) { \$plural = ""; if (\$i > 1) { \$plural = "s"; //reduce for mortality and spay \$c = \$i; //total live female cats \$d = \$i * .20; //percent died \$s = \$i * .35; //percent spayed \$i = \$i * .45; //remaining live female cats } \$b = \$a += 1; echo ""; } echo ""; echo "
 Year Female Cats Minus Died1 (@ 20% mortality) Minus Spayed2(@ 35% spayed) Breeding Female Cats # Kittens Born # Surviving Post Weaning3 Surviving Female Kittens4 Year " . round(\$b) . " " . round(@\$c) . " - " . round(@\$d) . " - " . round(@\$s) . " " . round(\$i) . " female cat" . \$plural . " will have " . round(\$i * 12) . " kittens " . round(\$i * 12 * .85) . " will survive and " . round((\$i * 12 * .85) * .465) . " 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
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