African Lions are the only species of big cats that voluntarily live in groups in the wild. As a result, their social structure has evolved to include specific mating rituals and rights. The pride is structured around the dominant male. His job is to protect the pride, and to mate with the females. Males fight to the death to defend and or obtain their position as dominant male in a pride. As a result, the dominant, and therefore breeding male is usually larger, fitter and stronger than those defeated in the race for the crown, thus ensuring the strongest genetic traits for their offspring.
The dominant female has primary mating rights, but the dominant male will mate with any female lioness in the pride. When the female is in season, she demonstrates her readiness by head rubbing and rolling onto her back. When she is ready, she will present her hindquarters to the male. The act of copulation is extremely quick, lasting less than a minute in most cases. During the actual act, the male lion mounts the female lion and grasps her neck with his powerful jaws. The act is repeated as often as physically possible over the approximately four days that the female continues to be in heat. This can amount to hundreds of individual acts of copulation. Despite all the repetition, mating is often unsuccessful, even though lions are able to induce ovulation rather than relying on an estrous cycle. The reasons for this lack of success are not well known.
The gestation period lasts about three and a half months, and litters range from two to six cubs. Cubs are utterly helpless at birth, and take a full two years to reach maturity. As a result, female lions only give birth about every two to three years. Lionesses within a pride often synchronize their ovulation in order to gestate and give birth around the same time. The sad fact is that only about 1 in 4 cubs will survive to adulthood.
Once cubs reach adulthood, they will eventually be banished from the pride in order to seek out prides of their own. Males, usually male siblings, will roam and eventually attempt to challenge a dominant lion for control of his pride. This prevents too much inbreeding within a pride.
References: http://www.bio.davidson.edu/people/vecase/Behavior/Spring2004/shelburne/mating.html
http://animals.nationalgeographic.com/animals/mammals/african-lion.html
