Sexual Maturity in Cats
At 8 to 10 months of age, domestic cats have completed most of their physical development. The breaking up of litters and the growing aggressiveness of what was once play weaken the ties that bind kitten siblings together. By the time they're about 18 months old, they are drifting into adolescence.
Cats will continue to play throughout their lives, but the frenetic energy of kittenhood gradually yields to a considerably more mellow, routine pace. Like adolescent humans, cats continue to grow and develop through to adulthood, becoming sexually and intellectually more mature along the way. Because domestic cats are provided with food and shelter and usually are spayed or neutered while kittens, an artificial environment is created for them, a perpetual kittenhood of sorts.
Depending on one's point of view, "fixed" domestic cats are either spared from or robbed of what would otherwise be a preoccupation defining much of their adolescence and adulthood: sexual activity. Just as they grow from helpless kittens to skilled hunters in a relatively brief period, cats quickly become sexually mature.
* The testes of males may become visible as early as 4 weeks of age. In domestic cats, males reach full sexual maturity, if they remain unaltered, between 9 and 12 months of age.
* Most females reach sexual maturity at around 10 months of age, although instances of much earlier pregnancies have been recorded.
* Many domestic breeds reach sexual maturity much later in life. Persians, in particular, may have trouble mating until well into their second year.
* Wild cats mature later as well. Cheetahs are sexually mature at close to 2 years, leopards at about 30 months, and tigers don't reach full maturity until 3 to 5 years of age.
Any breeding difficulties felines experience are usually the result of cats' solitary nature - a lack of available partners - rather than from physical incapability. The cycle of female sexual receptiveness is closely linked to exposure to daylight. Cats living near the equator can become pregnant at any time of the year. Dwellers of temperate climates are called seasonally polyestrus, meaning that they have many periods of heat, or estrus, within a certain season. These periods, which vary substantially among breeds and species, last for as little as two days and as long as two weeks.
For all cats, mating season can be hazardous. Depending on the density of the local male population, the competition for females can be fierce. Ferocious fighting often occurs between competing males or incompatible males and females. Especially among the big cats, serious and sometimes fatal injuries are quite common.
Normal tomcat anatomy
The reproductive tract of the tomcat consists of the penis, two testicles, the scrotum, the prostate gland, two bulbourethral glands and the ductus deferens (also called the vas deferens). Sperm produced in the testicles is carried via the ductus deferens into the urethra. The prostate and bulbourethral glands play a small role by contributing secretions found in semen. Cat owners occasionally are surprised to find that tomcats also have nipples, but these are nonfunctional.
An intact male cat's penis showing prominent spines. A neutered male cat's penis showing no spines present.
The penis is covered by a protective sheath called the prepuce. During licking and grooming, or sometimes during stimulating play, the penis may protrude from the prepuce. The tip of the penis is called the glans, and it is covered with 120 to 150 penile spines that are directed backward, away from the end of the glans. These penile spines start to appear at about 12 weeks of age and are fully developed at puberty. They are absent in neutered male cats, disappearing by six weeks after castration.
Sperm production by the testicles starts by the age of five to nine months. While sperm may be present in the testicles, the actual age at which mating begins will vary with physical condition, body size, and season. On average, the onset of puberty is at eight to ten months of age and at a body weight of 2.5 kg; however, significant variation among breeds is seen.
In addition to sperm, the testicles also produce testosterone, which regulates secondary sex characteristics, such as development of jowls, and male sexual behavior, such as mating and spraying. Testosterone levels in the blood vary widely (from 0 to 5.9 ng/ml) in an episodic fashion. It can be normal to find an undetectable level, especially in a single blood sample. Castration causes an almost immediate drop in the blood levels of testosterone, but viable sperm may still be present for up to six weeks.