Primatologist Susan Perry of the University of California, Los Angeles, who studied white-faced capuchin monkeys for 22 years -- the primates best known as organ grinders -- said even if a father wasn't a leader, other males in the community were more likely to take young males under their wing than their sisters, lavishing attention on the male youth showing him the ropes.
"Offspring, especially male offspring, raised in a group in which their father is the alpha male, throughout their juvenile phase enjoy a host of advantages over less fortunate monkeys," Perry said in a statement.
Perry said since 1990 she and her husband, Joseph Manson of the University of Iowa, and 122 students, volunteers and locals spent 79,000 hours observing 444 capuchins in Costa Rica.
The capuchins form cooperative groups with an alpha male, several subordinate males and many females to make a group of about 19, Perry found. The alpha males rise to their position -- and defend it -- by fighting off other males.
Initially, females mate exclusively with the alpha male and subordinate males wait to mate until the alpha male's daughters reach sexual maturity, a process that takes an average of six years. The regimes of most alpha males last about one year, but some lasted 18 years or just one day, Perry said.
Males reared in groups under the leadership of enduring alpha males are not the only beneficiaries of the old boys' network -- all male infants enjoyed considerable advantages over their sisters, Perry said.