Boys will be boys, even chimps

Behavior: Like humans, young female chimps tend to watch and learn from mom while the males are off to play.

Medicine & Science

April 19, 2004|By William Mullen | William Mullen,CHICAGO TRIBUNE

While young female chimpanzees in the African wild stick close to their mothers and learn useful tasks, such as how to fish tasty termites out of the earth, young male chimps - too busy romping, playing and being nuisances - don't pay much attention at all.

Such differences in girl vs. boy behavior might not surprise human parents, but scientists have shown that it extends to other primates, according to an article in the research journal Nature.

Since 1998, Elizabeth Vinson Lonsdorf, director of field conservation at Chicago's Lincoln Park Zoo, has spent several months a year in Tanzania's Gombe National Park studying how young chimps learn to use sticks, straw or grass to "fish" for food in termite mounds.

The subjects of her research are the offspring of the chimp clans made famous by Jane Goodall's path-breaking discovery 40 years ago that man is not the only species to use tools.

All of the 14 chimp young that Lonsdorf studied, each 11 years old or younger, learned the fishing technique by watching their mothers insert a tool into holes in the termite mounds. If done properly, termites will climb onto the spear, making for a delicious snack after the chimp pulls the spear out.

"Our findings indicate that female chimpanzees start to fish for termites at a younger age than males," wrote Lonsdorf, the Nature article's principal author, and "they are more proficient than males once they acquired the skill."

The females, she said, typically spent much of their childhood close to their mother's side. When they went to a termite mound to snack, the females carefully watched how mom inserts a stalk and learned to mimic her technique just so, including precisely how far to spear into the mound.

Male chimp offspring also follow their mothers to the mounds, said Lonsdorf, but they typically go off to play and don't learn the finer details of fishing.

"They are swinging in the trees, tumbling on the ground ... or jumping on their moms, trying to get them to join in the play," she said.

Genetically, no other animals are closer to humans than chimpanzees, which share 98.6 percent of the same DNA. Similar findings in learning differences in human children could mean, Lonsdorf said, that a "sex-based learning difference may therefore date back at least to the last common ancestor of chimpanzees and humans."

Research in Holland has shown that, among young human children, girls begin drawing earlier than boys and are better at it, while boys 2 years to 5 years old are better than girls at performing tasks requiring speed and strength.

"We know with human children that girls at an early age have superior fine motor skills," said Susan Levine, a University of Chicago child psychologist.

"They are better at manipulating objects with their hands, and they learn to say first words a little earlier."

Long-term research on great ape populations such as the Gombe chimps has drawn interest from scientists struggling to understand the origins of human behavior. Ape behavior offers a sort of window into human primal behavior, with chimpanzees, gorillas and orangutans having life expectancies and life stages similar to those of humans.

Like humans, chimpanzees have a long childhood, said Dario Maestripieri, an associate professor on the University of Chicago's committee on human development. Though chimp fathers don't play a role in rearing offspring, chimp youngsters depend on the care of their mothers until well after age 11.

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