section_path: Behavior/Reproduction
section_name: Reproduction
paragraph_text: Reproduction
  
  The cat secretes and perceives pheromones. Female cats, called queens, are polyestrous with several estrus cycles during a year, lasting usually 21 days. They are usually ready to mate between early February and August in northern temperate zones and throughout the year in equatorial regions.
  
  Several males, called tomcats, are attracted to a female in heat. They fight over her, and the victor wins the right to mate. At first, the female rejects the male, but eventually, the female allows the male to mate. The female utters a loud yowl as the male pulls out of her because a male cat's penis has a band of about 120–150 backward-pointing penile spines, which are about 1 mm (0.039 in) long; upon withdrawal of the penis, the spines may provide the female with increased sexual stimulation, which acts to induce ovulation.
  
  After mating, the female cleans her vulva thoroughly. If a male attempts to mate with her at this point, the female attacks him. After about 20 to 30 minutes, once the female is finished grooming, the cycle will repeat. Because ovulation is not always triggered by a single mating, females may not be 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, with the result that different kittens in a litter may have different fathers.
  
  The morula forms 124 hours after conception. At 148 hours, early blastocysts form. At 10–12 days, implantation occurs. The gestation of queens lasts between 64 and 67 days, with an average of 65 days.
  
  Based on a study of 2,300 free-ranging queens conducted from May 1998 and October 2000, they had one to six kittens per litter, with an average of three kittens. They produced a mean of 1.4 litters per year, but a maximum of three litters in a year. Of 169 kittens, 127 died before they were six months old due to a trauma caused in most cases by dog attacks and road accidents. The first litter is usually smaller than subsequent litters. Kittens are weaned between six and seven weeks of age. Queens normally reach sexual maturity at 5–10 months, and males at 5–7 months. This varies depending on breed. Kittens reach puberty at the age of 9–10 months.
  
  Cats are ready to go to new homes at about 12 weeks of age, when they are ready to leave their mother. They can be surgically sterilized (spayed or castrated) as early as seven weeks to limit unwanted reproduction. This surgery also prevents undesirable sex-related behavior, such as aggression, territory marking (spraying urine) in males, and yowling (calling) in females. Traditionally, this surgery was performed at around six to nine months of age, but it is increasingly being performed before puberty, at about three to six months. In the United States, about 80% of household cats are neutered.