It's been suspected that cheek pads -- which are usually only seen in one male in any given area, and the dominant male at that -- are a signal of fitness and status, making cheeky males more attractive to potential mates. Based on their observations, Banes and Vigilant believe this may be true.
They only studied one cheek-padded male (to study more, they'd have to have observed more than one group of orangutans) but he did father more offspring than any of his non-padded contemporaries. The other males were capable of producing offspring (of the 14 births that could be tested for paternity, four could be credited to the 12 subordinate males) but it seems that they only did so at the beginning and end of Kusasi's reign of dominance.
"These other males were typically reproductively successful at the beginning and end of Kusasi's dominant period, when the hierarchy was potentially unclear," Banes said in a statement.
In other words, flat-faced males only have a real shot when the dominant male -- the one who will develop puffy cheeks and a pendulous throat sac used to let out intimidating bellows -- is on the rise or decline.
That could help explain why males bother becoming dominant, the researchers explained. Dominant males require more food to sustain their large bodies, they're less mobile because of their size, and they're much more likely to die in fights with rivals. And some research suggests that males without cheek pads are playing a smart evolutionary game, too -- by going after the females that no dominant male would court. But at least in Kusasi's case, it really is good to be king.