EAT red meat if you want a boy baby, fish and vegetables for a girl鈥� Myths about how women can influence the sex of their baby abound, but for African buffalo, such effects are more science than fiction, and the main driver is the pitter-patter of tiny raindrops.
During wet periods, about 55 per cent of conceptions are male, but this falls to 45 per cent in dry seasons, says in the Netherlands. He analysed data from more than 3000 buffalo culled over 20 years in South Africa鈥檚 Kruger National Park.
Van Hooft found that some males carry a 鈥渟ex-ratio distorter鈥� gene which ensures that more males are conceived in the wet season, when food is abundant, making the fathers fitter and their sperm quality higher. Other would-be fathers carry a 鈥渟ex-ratio suppressor鈥� which does the opposite, producing a slight boost in female offspring conceived in the barren dry season.
Advertisement
Carriers of the 鈥渄istorter鈥� gene mate almost exclusively in the wet season, while the opposite is true of the 鈥渟uppressor鈥� carriers, which breed largely in the dry season. The system ensures that the population has fitter males: the physique and high sperm quality of wet-season fathers are passed on to the more abundant males of the next generation, says van Hooft.
Journal reference:
