Researchers discover female chimps learn faster than males

Geoffrey Ziezulewicz

Female chimpanzees heed their mothers more and are better learners than male chimpanzees, University researchers have discovered.

A recent study published in the scientific journal Nature reveals the sex-based differences.

The article sheds light on the chimp learning process by showing that young female chimps learn to catch protein-rich termites faster than their male counterparts.

To conduct research for the study, a group of University researchers monitored chimpanzees in Tanzania for eight months over four years.

The females – ages 11 and younger – were more attentive to their mothers’ termite-fishing techniques, while the males tended to fool around, said Anne Pusey, a University professor and co-researcher for the study.

“The males seem to have a shorter attention span, jumping around in the vines and swinging by their feet,” Pusey said.

Termite fishing is a technique certain chimp groups use to catch the insects, she said.

Chimps take sticks, straw or grass blades and insert them into termite mounds, which are similar to larger and harder ant hills.

When soldier termites bite the intruding objects, the monkeys pull the tool out of the tunnel and feast on them.

The researchers surveyed 14 monkeys, Pusey said.

On average, she said, female chimps learned the technique about a year and a half earlier than males.

“Males tended to do a lot of playing and not as much watching as the females do,” she said.

Frans de Waal, an Emory University professor who studies primates, said the project’s findings are important and new to the field by displaying parental connections and sex-based learning differences.

“The obvious explanation is that daughters are picking up the behavior of their mothers,” de Waal said. “Young females identify with their mother, whom they see as a role model, whereas young males do not.”

The researchers examined the mothers’ choices regarding length of sticks used and how far they stuck them in the termite mounds.

The young females tended to use the same-sized sticks and burrow them as deeply as their mothers did, Pusey said. Males did not show any correlation to their mothers’ methods.

“Females really do imitate some aspects of what their mothers do, rather than trying to figure it out themselves,” she said.

Researchers previously documented different behaviors and practices in varied chimp groups, Pusey said.

For example, some chimps in one part of Africa use rocks to crack hard-shell nuts, while other groups do not.

“There seems to be cultural differences in their local traditions and behavior that is passed on by observation,” she said.

Co-researcher Elizabeth Vinson Lonsdorf said the gender contrast between the chimps parallels research done on young children, which shows girls develop motor skills faster than boys.

Termite fishing

The study was conducted in Tanzania’s Gombe National Park during the rainy months from 1997 to 2001, Lonsdorf said.

Lonsdorf spent every waking moment with the chimp group, waiting for them to crave termites. Often, she said, they did not.

“They can go on a four-hour nap in the afternoon, and that can get really boring,” she said.

Termite fishing was especially popular during these months because the termite hills soften, and the insects burrow tunnels to the surface for reproductive purposes, she said.

Female chimps eat more termites because they are an easily attainable source of protein, Pusey said.

“Carrying a baby makes it difficult to hunt,” she said. “It is probably in their interest to catch termites as early as possible, and do it well, because it is going to be more important to them later on.”

The study also found females were more determined and consistent in their termite pursuits.

Though females go after the termites all year, males tend to only get them when the mounds are soft, Pusey said.

Lonsdorf said she will replicate the study in a chimp enclosure at the Lincoln Park Zoo in Chicago.

Despite assumptions to the contrary, termite fishing is no easy pursuit, Pusey said.

“They seem to have to thread it in, and pulling it out, they have to be careful,” she said. “I have never managed to get a termite out on a tool.”