National Pet Alliance

Are Owned Cats Causing an Overpopulation Crisis?

A National Pet Alliance Report

(c) 1994 Karen Johnson
Adapted from the Cat Fanciers' Almanac, October 1994

Consider 1000 owned cats vs. 1000 stray/feral cats.

              Table 1.  OWNED CATS AND STRAY/FERAL CATS

       ASSUME 1000 OWNED CATS       |    ASSUME 1000 STRAY/FERAL CATS
------------------------------------|------------------------------------
7 year life span.                   |  3 year life span.
                                    |
143 will die annually.  To sustain  |  333 will die annually
zero population growth, 143 cats    |  
will need to be replaced by new     |  350 will be female
births.                             |  
                                    |  97% of mature (approx. 6
500 will be female.                 |  months or older) females are capable
                                    |  of reproduction. Some will be
500 x 16% will have a litter prior  |  altered through trap/alter/release
to being spayed.                    |  programs. A few will be stray,
                                    |  previously owned cats.
 = 80 litters over 7 years time.    | 
 = 11 litters per year.             |  350 x 97% = 340 litters born
                                    |  2 times per year.
11 litters x 2.85 kittens = 31      |
kittens born from a population of   |  340 litters x 2.85 kittens live
1000 owned cats each year.          |  to age one year = 969 kittens.
                                    |  
143 for zero population, minus 31   |  969 kittens x 2 cycles per year
born = 112 below the level needed   |  = 1938 kittens per year, per 1000
to maintain the population of       |  unowned cats.
owned cats.                         |
                                    |  112 of these kittens are assumed
Owned cats produce 22% of the       |  to be adopted or obtained as
owned kittens necessary to          |  strays to sustain the owned cat
maintain the owned cat zero         |  population.
population level.                   |  
                                    |  1938 born minus 112 adopted = 1826
(A small percentage may have a      |  surplus/unwanted feral and stray
second litter prior to altering.)   |  kittens per year, per 1000 adults.
------------------------------------|------------------------------------
59% of the known cat population is  |  41% of the known cat population is
owned, according to the NPA survey. |  unowned, according to the NPA survey.
------------------------------------|------------------------------------

Food for thought:

If all stray and feral cats were caught and altered or killed, owned cats would have to produce an additional 22 litters per year per thousand cats to sustain zero population growth. This is twice the current rate. To balance out the cat population, it is necessary to either increase cat ownership or reduce kittens being born to strays and ferals, or both. Programs which address these solutions should be encouraged, i.e. elimination of limit laws, or Trap / Test / Vaccinate / Alter / Release programs (TTVAR).

Are Owned Cats Causing A Population Crisis?

Statistics

Cats vs. dogs at the shelter:

Litters produced by owned cats:

Stray cats fed, but not claimed:

Are owned cats altered?

Death rates:

Litter sizes:

Ratio of sexes:

Owned cats which disappear from their homes:

Random bred vs. pedigreed cats:


            Table 2.  ALTER STATUS OF OWNED DOGS AND CATS

                Santa Clara   Las Vegas,    Tufts,      MSPCA,
                County, CA    Nevada        Mass.       Mass.
                1993          1981          1991        1991
Female dogs    
  Spayed        -             77.22%        87.8%       -
  Whole         -             22.78%        12.2%       -
               
Male dogs       
  Neutered      -             26.49%        45.0%       -
  Whole         -             73.51%        55.0%       -

All dogs
  Altered       -             -             -           73%
  Whole         -             -             -           27%

Female cats
  Spayed        86.84%        85.7%         91.5%       -
  Whole         13.16%        14.3%          8.5%       -

Male cats
  Neutered      85.9%         78.95%        90.3%       -
  Whole         14.1%         21.05%         9.7%       -

All cats        
  Altered       86%           -             -           87%
  Whole         14%           -             -           13%



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