Orangutan Females Steal Food To Test Mates

10th July 2010

When males reacted violently or took the food back, the females screamed and tended to end the interactions much sooner than when the male tolerated the stealing.


Evolutionarily, the behavior makes sense, experts say, since relationships with aggressive males can be extremely damaging for females.


Males who are aggressive to other males may attract females. But when a male is aggressive to a female, he limits her ability to choose when and with whom she mates, since she faces attacks if she does not do as the male wishes, explained lead author Maria van Noordwijk at the University of Zurich.


"She could endure injuries, from bruises to broken bones, if his attacks were to knock her out of a tree," van Noordwijk said.


The researchers did not see the females give immediate sexual favors in return for the males tolerating the food stealing.


But, van Noordwijk said, "we think the stealing allows females to test males for their tendency to be aggressive toward them so they can determine whether they are worth further associating with."


These findings were published online March 10 by the journal Behavioural Ecology and Sociobiology.