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Are female mountain goats sexually conflicted over size of mate?

November 18, 2009

Mountain goats are no exception to the general rule among mammals that larger males sire more and healthier offspring. But University of Alberta researcher David Coltman has found a genetic quirk that might make female mountain goats think twice about their romantic partners.

Big, heavy males mountain goats shove lightweight Romeos aside taking the eligible females for themselves. The larger males pass their physical attributes and mating success to their male heirs. But Coltman's data shows the daughters of the big, bruisers are routinely smaller and less fit than females produced by physically more modest fathers. Nature can be cruel and life on the side of a mountain favours bigger, healthier animals, both male and female.

Coltman's research shows that this anomaly could have implications for female mate choice, since a female that mates with a large, dominant male can expect to have larger sons, but smaller and less fit daughters. The research also poses the question of why female offspring sired by the dominant male would be compromised. Another question the study raises is; what if any consideration does the size of their daughters have for would-be mothers? Could this be a factor weighed by a sexually mature female when courted by males that come in a variety of sizes?

University of Alberta