Inside Iowa State

Feb. 27, 2009

Anthropologist Jill Pruetz will give the spring Presidential University Lecture on March 2. Photo by Bob Elbert.

Pruetz to explore human evolution through savanna chimps in Presidential University Lecture

by Mike Ferlazzo, News Service

Iowa State associate professor of anthropology Jill Pruetz says she is gaining a unique insight into human evolution through her study of savanna chimpanzees in southeastern Senegal. And she's not alone.

Her discovery two years ago that the chimps at her Fongoli site are the first nonhumans to routinely use primitive spear-shaped tools to hunt other vertebrates rocked the science world.

In a new paper, Pruetz reports that the same chimps now are sharing food and hunting tools -- documenting another uncommon chimpanzee behavior previously considered, by many scholars, to be a defining human characteristic.

Pruetz will discuss those discoveries and more in the Spring 2009 Presidential University Lecture on Monday, March 2. Her presentation, "Savanna Chimpanzees and Our Understanding of Human Evolution," will begin at 8 p.m. in the Memorial Union Sun Room. The event is free and open to the public. A reception and poster display of student research will precede the lecture at 7 p.m. in the South Ballroom.

"Anthropologists study primates to get a better understanding of human evolution," Pruetz said.

The differences between savanna chimps and chimps in the forest "leads you to think that this savanna environment can produce some changes that take them in a human-like direction," she said. "No one ever assumes that chimps will become human, but these stresses [from the extreme hot, arid environment] result in things that are along the lines of what we predict happened with early hominids -- apes that lived six million years ago."

Chimps who share

In her latest study, which she'll discuss in the lecture, Pruetz reports that male chimpanzees shared plant foods and tools with an unrelated female, who was not looking to mate. Both the males and females also shared their meat, an uncommon sharing behavior when dominant males are involved.

"With chimps, you do see sharing with meat. But at other sites, if females have the meat -- and they don't hunt at others' sites like they do mine -- males will take [the meat] away from them," Pruetz said. "So really it's more tolerance and affiliation in this case."

Previous research, including a 1986 book by famed primatologist Jane Goodall, reported that meat sharing among chimps is thought to benefit the donor through reciprocity or trade -- such as the "meat for sex" hypothesis.

In her lecture, Pruetz also will report on another paper she's authored on the chimpanzees' reaction to fire. And she plans to share the heartwarming story and video she shot earlier this month when she reunited a 9-month-old chimpanzee -- who had been taken by hunters at her Fongoli site -- with its mother.

Pruetz, a National Geographic Emerging Explorer for 2008, said her presentation "should highlight some of the near-human behavior we've reported seeing the chimps exhibit."

Her discovery that chimps are using spear-shaped tools to hunt smaller primates (bush babies) was ranked second among Wired News' "Top 10 Scientific Breakthroughs of 2007," and featured prominently last year in "Ape Genius," a Nova Series/National Geographic television special that aired on the Public Broadcasting System. It also was the subject of a feature story in National Geographic magazine.

President Gregory Geoffroy created the Presidential University Lecture Series in 2003 to highlight the expertise and excellence of Iowa State faculty.

Jill Pruetz will present "Savanna Chimpanzees and Our Understanding of Human Evolution" at 8 p.m. March 2 in the Memorial Union Sun Room.