| |
Chimpanzee's behavior
Share and share alike
A new study by Iowa State University anthropology professor Jill Pruetz reports that chimpanzees at a research site at Fongoli in Senegal frequently share food and hunting tools with other chimps.
| |
Pruetz
|
Coauthored by ISU anthropology graduate student Stacy Lindshield, their study is posted online in Primates and will be published in a future issue of the journal.
The researchers witnessed 41 cases of Fongoli chimpanzees willingly transferring either wild plant foods or hunting tools to other chimpanzees. While previous research by primatologists had documented chimps transferring meat among other non-relatives, this is the first study to document non-meat sharing as part of the chimpanzee's behavior.
"They're [i.e., the Fongoli chimps] not the only chimps that share, but in terms of the resources that we cover here, that is unique," said Pruetz. "I guess all chimps share meat, but they don't share plants or tools. Yet they do here, in addition to meat. It was intriguing when we first started seeing these events."
The researchers document a frequency of sharing previously unreported for chimpanzees. The chimps commonly transferred meat and wild plant foods, but they also transferred tools, honey and soil. Most of the transfer behavior was classified as recovery or passive sharing, with females commonly taking food from males -- with much of that taking place from dominant to subordinate recipients. Of the 41 witnessed events, Fongoli male chimps transferred wild foods or tools to females 27 times.
|
Nickel, an adult female, and Jumkin, an adolescent male, share
plant food at the Fongoli research site, a previously unreported
aspect of the chimpanzee's behavior.
|
Pruetz sees some of the sharing behavior between males and females as evidence for a "food for sex" theory. The researchers found that both adult females in estrus [the period of maximum sexual receptivity of the female] and adolescent females cycling to estrus were more likely to receive food from adult male chimps. Pruetz says that the male chimps may use food transfer as a future mating strategy with the adolescent females, particularly since there are a relatively small number of females in the Fongoli community.
"It may be used as a strategy [by the male chimps], anticipating a longterm gain on their behavior," she said. "We see that in baboons who have special friends."
As the only habituated community of chimpanzees living in a savanna environment, the researchers conclude that Fongoli provides detailed information on the effect of an open, dry and hot environment on social behavior and organization. Pruetz thinks that the chimpanzees' behavior may also shed some light on how the earliest humans first came to share.
| |
Location of Senegal
|
"There are aspects of human behavior, and I think that's interesting because it's not exactly the same, but it may give you an idea of how it [sharing among early humans] started," Pruetz said. "It's at least one scenario and how it could have come about in our own lineage."
|
Adapted from materials obtained from the AAAS |
|
