Fig. 1. Ostriches (Struthio camelus) cope with large thermal fluctuations in their native habitat, reproducing successfully across Africa from the Western Cape to the deserts of Southern and Northern Africa.

a Courtship by a male ostrich (right) towards a female (left) in one of the enclosures (n = 197) at the study site used to keep a single breeding pair (photo: CKC). b Data structure of fertility traits obtained from 1998 to 2018 at the study site of Oudtshoorn Research Farm in the arid Klein Karoo region of South Africa. Sperm viability data was not available for all of the solitary males where measures of sperm numbers were obtained (sperm viability: n_ind = 18, n_years = 7, ${\overline{x}}_{\mathrm{years}\mathrm{per}\mathrm{ind}}=2.7$). See also Supplementary Table 1 for detailed overview of sample sizes. c Geographic range (green) of the ostrich⁹³ with the study site marked by an asterisk. d Monthly temperature range was calculated by estimating the range of temperatures of each month and then calculating the mean of this across all months⁹⁴.