by Susana Polo | 2:13 pm, March 30th, 2012
The Trivers-Willard hypothesis is a theory that states that in species that don’t mate in pairs but polygynously (males mate with many females), evolutionary pressure will have created reproductive biology that responds to periods of easy living and periods of hard living by actually skewing the normal 50% chance of producing offspring of one sex or the other. In good times, things would skew towards male offspring, because the easier it is to raise a healthy kid, the better chance your genes have of becoming that dominant male that gets to reproduce with lots of females. In bad times, however, things would skew towards the female. If raising the best male is a longer shot, at least a healthy female will get to reproduce with the healthier males.
Both ground squirrels and red deer populations correlate with the theory, and now, at least according to a study published in Proceedings of the Royal Society, humans do too well. And yes, we’re generally considered to have descended from polygynous apes.READ MORE