Are Owned Cats Causing an Overpopulation Crisis?
A National Pet Alliance Report
(c) 1994 Karen JohnsonAdapted from the Cat Fanciers' Almanac, October 1994
Consider 1000 owned cats vs. 1000 stray/feral cats.
- Which group is having the most kittens?
- Which group is sustaining itself by reproduction?
- Which group is handled more by animal control and shelters?
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:
- At the third largest shelter in the country, Santa Clara County, California, 36% of the animals handled are dogs, vs. 64% cats.
- Euthanasia totals are 80% cats and 20% dogs.
Litters produced by owned cats:
- A Massachusetts SPCA (MSPCA) study in 1991 shows 20% of cats have a litter prior to being altered.
- A National Pet Alliance (NPA) study of Santa Clara County in 1993 concluded 16% of female cats have a litter prior to being altered.
- A 1981 study of Las Vegas, out of Kansas State University, found that 16% of the unspayed females reproduced.
Stray cats fed, but not claimed:
- A HSUS national survey in 1992 found nearly 25% of households feed stray cats.
Are owned cats altered?
- The MSPCA study reported 87% of owned cats were already altered.
- The Las Vegas study from KSU found 86% of owned female cats were spayed.
- A report from Tufts University showed 91.5% of owned female cats were spayed.
- The Santa Clara County survey found 86% of owned cats were altered.
Death rates:
- Dr. Roger Nassar, who conducted the Las Vegas study, concluded the average life span of the owned cats, based on respondents' answers, was 7.02 years.
- Ellen Perry Berkeley, in her book Maverick Cats, from various sources indicates the life span of feral cats to be 2-3 years.
- Also from Maverick Cats, we find only 33% of feral kittens are alive at age 1 year.
Litter sizes:
- Average domestic cat can have 4.25 kittens, and 2.1 litters per year according to Dr. Niels Pedersen in Feline Husbandrv; 1/3 will be dead by the age of one year, with most of the deaths occuring at birth, or shortly thereafter.
Ratio of sexes:
- 50/50 in owned domestic cats.
- 35% female / 65% male among feral cats, according to Maverick Cats,
Owned cats which disappear from their homes:
- From the Las Vegas study, 2.7% of the cat population strayed each year.
- From the NPA study, 0.58% of owned cats strayed with no hint to their fate.
- The NPA survey showed 10% of households fed stray cats.
Random bred vs. pedigreed cats:
- According to Cat Fanciers' Association (CFA) statistics, no more than 3% of the owned cat population is pedigreed.
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%
Bibliography
- Berkeley E.P., Maverick Cats. New England Press,1982:26-27, 54-55.
- Handy, F.L., "Measuring your community's pet population, owner attitudes" Shelter Sense, Vol 16, No. 5, May 1993:3-12.
- Johnson K.J., Lewellyn J., "National Pet Alliance survey report on Santa Clara Country's Pet Population" Cat Fanciers' Almanac, Jan. 1994
- Manning A.M., A.N. Rowan, "Companion animal demographics and sterilization status: Resuls from a survey in four Massachusetts towns" Anthrozoos, Vol V, No. 3.
- Mosier J.E., L.W. Williams, R. Nassar, "Study of feline and canine populations in the greater Las Vegas area" Am J Vet Res., Vol 45, No. 2:282-7.
- Pedersen, Niels, Feline Husbandry. American Veterinary Publications, 1991:133-135.