cats only mate when the queen is "in heat". heat periods occur about every two weeks and last 4 to 6 days. mating in cats is a spectacular event. several toms may be attracted to a [queen] in heat. the males will fight over her, and the victor wins the right to mate. at first, the female will reject the male, but eventually the female will allow the male to mate. the female will utter a loud yowl as the male pulls out of her. this is because a male cat's penis has a band of about 120-150 backwards-pointing spines, which are about one millimeter long. when the penis is withdrawn, the spines rake the walls of the female's vagina, which is a trigger for ovulation. after mating, the female will wash her vulva thoroughly. if a male attempts to breed with her at this point, the female will attack him. after about 20 to 30 minutes. once the female is finished grooming, the cycle will repeat.