Can a single female cat and her offspring really produce 420,000 cats over just seven years? This article examines the validity and origin of this commonly cited statistic, concluding that this statistic is likely an urban myth. A lower estimate is provided and substantiated by research by biologist Michael Stoskopf, who documented six kittens per year with a 75% kitten mortality.

Hundreds of media reports have used the statistic that a single female cat and her offspring produce 420,000 cats over seven years. However, research by reporter Carl Bialik failed to produce the origin of this statistic. It is believed that the statistic may have been derived from “assuming that each female cat survives into adulthood, and along the way begins reproducing herself at around six months, then continues creating litters every half year. That means 14 cycles of exponential growth over seven years.” However, this fails to take into account kitten mortality, which could skew the estimate significantly.

Instead, The Feral Cat Times published a number closer to 100, citing research by Michael Stoskopf of North Carolina State, which showed that three quarters of feral cats’ kittens die before reaching reproductive age.