Cats are seasonally polyestrous,
which means they may have many periods of heat over the
course of a year. A heat period lasts about 4 to 7 days
if the female is bred; if she is not, the heat period lasts
longer.
The male cat's penis has spines which point
backwards. Upon withdrawal of the penis, the spines rake
the walls of the female's vagina. The female needs this
stimulation for ovulation to begin. Because this does not
always occur, females are rarely impregnated by the first
male with which they mate. Furthermore, cats are superfecund;
that is, a female may mate with more than one male when
she is in heat, meaning different kittens in a litter may
have different fathers.
The reproduction process can be very loud,
as both cats vocalize loudly. If one is not used to the
sounds of cats mating, it sounds very much like a cat fight.
The gestation period for cats is approximately
63-65 days. The size of a litter averages three to five
kittens, with the first litter usually smaller than subsequent
litters. Kittens are weaned at between six and seven weeks,
and cats normally reach sexual maturity at 4-10 months (females)
and to 5-7 months (males).
Cats are ready to go to new homes at about
10 weeks old, or when they are ready to leave their mother.
Cats can be surgically sterilized (spayed or neutered) as
early as 6-8 weeks to limit unwanted reproduction. This
surgery also prevents undesirable sex-related behavior,
such as territory marking (spraying urine) in males and
yowling (calling) in females. If an animal is neutered after
such behavior has been learned, however, it may persist.
Blue-eyed cats with white fur have a higher incidence of
genetic deafness. Over 200 heritable genetic defects have
been identified in the cat, many of which are homologous
to human inborn errors. Specific metabolic defects have
been identified underlying many of these feline diseases.There
are several genes responsible for the hair color identified.
The combination of them gives different phenotypes. See
Cat coat genetics.
Features like hair length, lack of tail
or presence of a very short tail (bobtail cat) are also
determined by single alleles and modified by polygenes.
A Cat Genome Project is sponsored by the
Laboratory of Genomic Diversity at the U.S. National Cancer
Institute Frederick Cancer Research and Development Center
in Frederick, Maryland. The research focuses on development
of the cat as an animal model for human hereditary disease,
infectious disease, genome evolution, comparative research
initiatives within the family Felidae, and forensic potential.
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