THURSDAY, April 15, 2004 (HealthDayNews) -- It's a familiar enough scenario, albeit one that might be termed sexist: The girls spend more time by their mother's side, learning how things are done in the kitchen while the boys roughhouse nearby, paying scant attention to the parent's lessons.
This time, though, the tale describes young chimps fishing for a nutritious meal of termites. And, because they are watching their mothers so closely, it seems, young girl chimps get a head start in the termite fishing arena of life. They start earlier, spend more time at it, and are generally better at it than boy chimps.
Before drawing any gender-based judgments regarding chimp skills or lack thereof, however, bear in mind the activities favored by boys (swinging and playing) could be considered good practice for hunting.
The authors of an article detailing these findings in the April 15 issue of Nature said the differences they observed are similar to gender-based differences found in human children. This suggests the differences have an ancient origin in the common ancestor of chimps and humans.
"Culture must be passed down in some way," said study author Anne E. Pusey, a professor of ecology, evolution and behavior at the University of Minnesota in St. Paul. "This is the first time we've taken a detailed look at how much detail [the chimps] learn by watching others. This opens up a whole line of interesting questions."
Except for humans, chimpanzees use tools for more purposes than any other species. Jane Goodall first observed chimps inserting sticks into termite mounds to extricate termite meals. The sticks, made out of vegetation, were a simple tool.
Since different chimp communities can use tools differently, the current researchers set out to see how the behavior was passed on to the community's offspring.
For four years, the researchers observed and videotaped 14 animals under the age of 11 and their mothers while termite fishing.
Daughters tended to closely follow their mother's technique, especially when it came to how deeply they inserted the stick. Sons did not.
Daughters tended to start fishing at about 31 months old, vs. 58 months for the boys, a difference of 27 months.
Females also extracted more termites per dip than the males. Males' reaction to being surpassed was not noted.
At the same time, the mothers did not appear to interact any differently with sons or daughters and did not seem to engage in any active teaching. The learning, then, would seem to take place through observation, with girl chimps spending more time than boys watching the mothers fish. The males were at the termite mound, but were playing instead of fishing.
According to the authors, this behavioral distinction makes sense, as female monkeys are often pregnant or taking care of an infant and therefore unable to hunt. Fishing for termites, which are rich in protein and fat, is easy enough to do even when saddled with maternal responsibilities.
Nora Newcombe, a professor of psychology at Temple University in Philadelphia, found the extrapolation to humans somewhat surprising. "The sort of literature that I thought they might relate it to they didn't at all," she said. "They cite studies in things like human movement and occupational and physical therapy journals. They seem to be going along the lines of fine motor skills that differ in human children."
Perhaps more to the point, Newcombe said, would be issues of activity and attention -- human boys tend to be more physically active, while human girls tend to have more attention skills. Also, researchers have so far found no gender differences in the ability to imitate.
"The fact that there aren't any sex differences in imitation, coupled with activity levels and attention, strongly suggest that there are attention and activity level kind of things are going on here," Newcombe said.
More information
The University of Minnesota Discover Chimpanzees site has a video of chimpanzees eating termites and more on Gombe National Park, Tanzania.
