The gestation period lasts a little over 165 days. Births occur in late March or April, with a variable number of females being barren. Most subspecies give birth to a single lamb, though in some races, twins are not uncommon and even as many as five have been born at once. At birth, the lambs weigh . The newborn lamb and mother ewe stay around where the birth occurs overnight and, on the next day, both usually walk together. Lambs often play in groups, jumping up and down together, sometimes being joined by their mothers. Weight gain is often quite fast and the lambs may weigh 10 times their birth weight by their first birthday. Females often attain their maximum mass by two years of age, but males appear to continue to grow larger and heavier in their third and fourth years. Milk teeth develop around three months of age, with a full set of teeth developing by around six months. By the time their teeth develop, lambs are capable grazers, but the ewes continue nursing them from August to May of the following year. Most argali live five to 10 years, but are capable of living 13 years in the wild.