Female Orangutans Prefer Males With Padded Cheeks

Posted on September 1, 2015

Male Oranguatan with cheek pads

A team of scientists have been studying the reproductive success between cheek-padded males and males without cheek pads. Some male orangutans develop large cheek pads or flanges (like the one pictured above) while others do not. The scientists found that male orangutans with the large cheek pads are more likely to father offspring.

The researcher teams was led by Graham L. Banes and Linda Vigilant of the Max Planck Institute for Evolutionary Anthropology. They followed the reproductive success of a male orangutan named Kusasi. Kusasi was the dominant male at Camp Leakey in Indonesia's Tanjung Puting National Park for a decade. He has large cheek pads. The scientists say that usually only the dominant male orangutan in any given area has cheek pads. Kusasi became a father more often than any other male during his decade as the dominant male. The other males succeeded in fathering offspring only at the beginning and at the end of Kusasi's dominance.

Banes says in a statement, "We performed paternity testing to see which of these males were fathering offspring at Camp Leakey, and to quantify Kusasi's reproductive success. Paternity could be assigned to 14 candidate offspring, conceived across multiple decades, ten of which were fathered by Kusasi."

A research paper on the study can be found here in the journal, Behavioral Ecology and Sociobiology. The scientists write in the paper, "We conclude that orang-utan male bimaturism is consistent with an evolutionarily stable reproductive strategy and that reproduction within the range of a dominant, flanged male is highly skewed in his favour, while unflanged males may largely wait for reproductive opportunities."

Photo: Bpk Bain