According to Bourquin (2008), the average breeding female in southern Africa is between . Earlier studies support that breeding is often inconsistent in females less than and clutch size is smaller, a female at reportedly never lays more than 35 eggs, while a female measuring can expect a clutch of up to 95 eggs. In "stunted" newly mature females from Lake Turkana measuring , the average clutch size was only 15. Graham and Beard (1968) hypothesized that, while females do continue to grow as do males throughout life, that past a certain age and size that females much over in length in Lake Turkana no longer breed (supported by the physiology of the females examined here); however, subsequent studies in Botswana and South Africa have found evidence of nesting females at least in length. In the Olifants River in South Africa, rainfall influenced the size of nesting females as only larger females (greater than ) nested during the driest years. Breeding females along the Olifants were overall larger than those in Zimbabwe. Most females nest only every two to three years while mature males may breed every year.