The average gestation period, or the length of pregnancy, of a lion is 108 days. The exact number of days vary, as some give birth after 105 days, and others carry their babies up to 115 days.
Lions are ready for reproduction when they are 2 to 3 years old. A male lion of this age goes in search of a pride of his own. A female lion is in estrus, the period when female mammals are sexually receptive and fertile, for 4 to 8 days. If the mating does not result in pregnancy, the estrus cycle repeats after approximately 90 days. The male lion and the female lion are constantly together during the mating period, and it is typical for both lions to refrain from eating the entire time.