An unspayed female cat, her mate and all of their offspring, producing 2 litters per year, with 2.8 surviving kittens per litter can total:

                                    1 year: 12
                                    2 years: 67
                                    3 years: 376
                                    4 years: 2,107
                                    5 years: 11,801
                                    6 years: 66,088
                                    7 years: 370,092
                                    8 years: 2,072,514
                                    9 years: 11,606,077

An unspayed female dog, her mate and all of their puppies, if none are ever neutered or spayed, add up to:

                                    1 year: 16
                                    2 years: 128
                                    3 years: 512
                                    4 years: 2,048
                                    5 years: 12,288
                                    6 years: 67,000