Typically, species in which dads play a major role in parenting are also those where couples pair up for the long-term, such as siamangs—a type of gibbon—and owl monkeys.
(Related news: "Monkey Dads Gain Weight With Their Mates, Study Says" [February 6, 2006].)
But baboon dads appear to get involved because their effort pays off for their offspring.
The study appears this week in the journal Proceedings of the National Academy of Science.
It Pays to Parent
Daughters born to high-ranking moms mature earlier—a lifelong advantage—and during their lives typically give birth to half an infant more on average than other females.
(Related news: "Baboon Study: Sociable Moms Have Healthier Young" [November 13, 2003].)
"We're thinking that the effect of the fathers' [influence may be] similar," study author Alberts said.
Elizabeth Susman of Pennsylvania State University suggests that the role stress reduction plays may be linked to the endocrine system.
"When you reduce stress, you increase the probability that reproduction would occur," Susman explained.
"If you're under high-stress conditions, your sex steroid hormones are suppressed, which would delay puberty."
Opposite Effect
Susman also pointed out, as did the new study, that many studies on humans find children raised in homes without a father present actually reach sexual maturity faster.
"It has been found in a number of studies ... [but] there is no explanation that has worked across all studies," Susman said.
It's also unknown how baboon dads produce the opposite effect, said UCLA's Silk.
But researchers now know that baboons consider parenting to ensure survival of their offspring important, she said.
"Now people will go back and ask how and why males have this effect," she said. "[Until] now you wouldn't have asked this question—and it's a really relevant question."
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