Fichtel and her colleagues argue that appearing male has evolved as a defense to keep females from attacking until the masquerading females are strong enough to handle it. That tends to be between 7 and 17 weeks of age.
(Related: "Rainfall Helps Baby Lemurs Survive, Tooth Study Shows" [November 14, 2005].)
Red-fronted lemurs are not the only primates whose youngsters are colored differently than adults.
In other species this disparity has often been explained as an adaptation that makes infants more noticeable to groupmates. Adults are then more likely to care for and protect infants, Fichtel added.
The study appears in the July issue of the Journal of Physical Anthropology.
Female Dominance
"This provides a fresh perspective into why some primate offspring have a dramatically different coat color," said Sylvia Atsalis, a primatologist at Lincoln Park Zoo in Chicago.
"It tickles scientific minds to think—through a new perspective—about a condition that occurs in many species," she added.
More in-depth analyses should be made into female lemurs and their behaviors, other scientists said.
"There has been a long-running argument about how aggressive red-fronted lemurs are to each other," said Alison Jolly, a primatologist at the University of Winchester in the United Kingdom.
"Most of their social life is cuddling and grooming, [but] once in a long while females viciously throw other females out of the group, or more rarely, they have been seen to kill and actually eat another animals' infants," she said.
"The question is, Is infanticide or targeting so rare that it couldn't have much influence over evolutionary time?"
(Read: "Ecotourism Driving Tibetan Monkeys to Infanticide" [July 20, 2007].)
Patricia Wright, a primatologist at Stony Brook University in New York, added that genetic tests should be done to see how lemurs perceive color.
"We've only recently learned that not all lemurs see color," Wright said.
"Sometimes only females have color vision, a trait that makes males dependent upon them for finding berries and secures female dominance."
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