'Cheeky' Male Orangutans a Hit with the Ladies
Males with the cheek-padding feature on their faces have better success at reproducing, a new study suggests.
Some male orangutans sport a special facial feature: cheek pads -- large folds of flesh on either side of the face. It turns out that this catcher's-mitt-with-a-face-in-the-middle look may be a key to being especially successful siring offspring.
Cheek pads are seen only on the dominant males in a given area, and researchers from the Max Planck Institute for Evolutionary Anthropology wanted to know why a dominant male would even bother developing them, when his life was tough enough already and he didn't need them to father children (subordinate males, without cheek pads, can also have perfectly good reproductive success).
"Dominant males have to find and consume more calories. Their movement is restricted as a result of their size, and fights with neighboring dominant males have been known to result in death," explained study co-author Graham L. Banes, in a press release. "So, why would a male develop cheek pads if he can father offspring without?"
To find out, Banes and co-author Linda Vigilant spent eight years gathering data on orangutans in Camp Leakey, in Indonesia's Tanjung Puting National Park. They compared the reproductive success of its dominant male of the era, Kusasi, with that of the camp's subordinate males.
The team's extensive paternity testing program, using DNA sampling of fecal matter, showed that Kusasi, he of the handsome cheek pads, was indeed a boss, fathering many more children than did the subordinate males.
The answer, then, to the researchers' question of 'why cheek pads when you don't particularly have to?' seemed to be that the feature skews things significantly enough in a cheek-padded orangutan's favor to make it worth the evolutionary effort.
And what of the poor subordinate male orangutans of Camp Leakey? Were they forever playing second fiddle to Kusasi? Not quite. The scientists found that nature opened a window of sorts for them.
"These other males were typically reproductively successful at the beginning and end of Kusasi's dominant period," said Banes, "when the hierarchy was potentially unclear."
Banes and Vigilant's findings have been published in the journal Behavioral Ecology and Sociobiology.
This flanged (cheeked) male orangutan has the kind of cheeks the ladies seem to prefer.
On January 7, this shaggy little bundle of joy was delivered by Caesarean section at the University of Minnesota Veterinary Medical Center. Her mom is a 27-year-old Sumatran orangutan named Mariska, from the
in Saint Paul, Minn. We thought you'd enjoy having the baby girl brought to your attention.
It was mother Mariska's second required C-section, both of which were performed at the university's medical center. "C-sections are very rare in that there are only about a dozen recorded within the International Orangutan Studbook that has tracked more than 1,200 births in captivity throughout history," said Como Zoo's primate keeper Megan Elder.
The new arrival weighed in at a spry 3.45 pounds.
She and her mom certainly drew a crowd. The obstetrical team boasted more than a dozen professionals -- from the disciplines of human and animal neonatal intensive care, human maternal-fetal medicine, veterinary surgery, veterinary anesthesiology, and nutrition.
The newborn should be proud. Her mother Mariska is considered one of the most genetically valuable female Sumatran orangutans in North America and was recommended for breeding by the Association of Zoos and Aquariums and the Orangutan Species Survival Plan.
The little girl of the hour was bottle fed by Como Zoo staff while her mom was recovering from the surgery. She and Mariska would soon be reunited at Como Zoo.
About 200 orangutans are currently on exhibit in zoos throughout the U.S., Como Zoo notes. In the wild, they're found primarily in Sumatra and Borneo. Orangutan populations have tumbled downward and the species is under the threat of extinction. Commercial logging, agriculture, hunting and poaching all have contributed to the animal's decline. So it's always happy news when a baby gives a small ray of hope to a species in trouble.