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[Josh Greenman <joshg1973 AT yahoo.com>]

http://www.newscientist.com/news/news.jsp?id=ns99994886

Young female chimps outlearn their brothers

18:00 14 April 04

NewScientist.com news service

Young female chimps are faster and better learners than young male 
chimps, suggests a new study, echoing learning differences seen in 
human girls and boys.

While young male chimps pass their time playing, young female chimps 
carefully study their mothers. As a result, they learn how to fish for 
tasty termite snacks over two years before the boys.

Elizabeth Lonsdorf, now at Lincoln Park Zoo in Chicago, US, and 
colleagues at the University of Minnesota, Saint Paul, spent four years 
watching how young chimpanzees in the Gombe National Park in Tanzania 
learned "cultural behaviour".

The sex differences in learning behaviour were "consistent and 
strikingly apparent", says the team. The researchers point out that 
similar differences are seen in human children with regard to skills 
such as writing.

"A sex-based learning difference may therefore date back at least to 
the last common ancestor of chimpanzees and humans," they write in the 
journal Nature.

Late starters

Chimps make flexible tools from vegetation and then insert them into 
termite mounds, extract them and then munch the termites clinging onto 
the tool. The researchers used video cameras to record this feeding 
behaviour and found that each chimp mother had her own technique, such 
as how she used tools of different lengths.

Analysis of the six infants whose aged were known showed that girl 
chimps were an average of 31 months old when they succeeded in fishing 
out their own termites, where the boy chimps were aged 58 months on 
average.

Females were also more skillful at getting out more termites with every 
dip and used techniques similar to their mothers' where the males did 
not.

Instead of studying their mothers, the boy chimps spent a significantly 
greater amount of time frolicking around the termite mound. Behaviours 
such as playing or swinging might help the male infants later in life 
when typically male activities like hunting or fighting for dominance 
become important, suggest the researchers.

Protein source

Lonsdorf adds that there are just two main sources of animal protein 
for chimps - the termites or colobus monkeys.

"Mature males often hunt monkeys up trees, but females are almost 
always either pregnant or burdened with a clinging infant. This makes 
hunting difficult," she says. "Adult females spend more time fishing 
for termites than males."

So becoming proficient at termite fishing could mean adult females eat 
better. "They can watch their offspring at the same time. The young of 
both sexes seem to pursue activities related to their adult sex roles 
at a very young age."

Journal reference: Nature (vol 428, p 715)