The naked chef

CHIMPANZEES are on their way to becoming half-decent chefs. Captive chimps in 
Madrid have begun to purée their own fruits and vegetables, in what looks 
like the first case of an ape transforming food to improve its taste and 
texture. 

Chimps use all sorts of clever techniques to obtain food, such as fishing 
termites out of mounds with sticks and bashing palm nuts open with rocks. But 
these tricks do not alter the quality of the food. "These are not cases of 
transformation of food in the human way," says Samuel Fernández-Carriba, a 
primatologist at the Universidad Autónoma in Madrid. "Transformation involves 
things like grinding and heating." 

The first chimp to perform the new trick was Linda, who was brought to the 
university zoo in 1992 after her previous owner had removed all her teeth to 
avoid being bitten. When she had been at the zoo about a year, the keepers 
noticed she was managing to eat apples by rubbing them along a sharp corner 
in her enclosure so that pulp and juice ran out on the wall. She would lick 
the mashed fruit off the wall and then rub the apple some more. Six other 
chimps in the same enclosure soon began to imitate her. Now the whole group, 
except the alpha male and female and an infant, have picked up the technique. 

Fernández-Carriba and his colleagues Angela Loeches and Ana Morcillo have now 
watched the chimps puréeing their food for more than 450 hours. Rather than 
just mashing up fruit any old way, the other chimps have adopted Linda's 
means of preparation. They all rub the fruit on a sharp corner for about 10 
seconds and then lick off the purée. Because the chimps copy the action in a 
stereotypical fashion, the researchers conclude that it is a culturally 
transmitted ritual. Chimps are known to have passed on around 40 other 
behaviours in the same way. 

The gourmet chimps eat apples, carrots, lemons and oranges by rubbing, which 
changes not only the texture but also the flavour of the food. And since they 
choose to take the time preparing each dish, they may get greater enjoyment 
or satisfaction from the result, says Fernández-Carriba. 

It is unclear whether food transformation exists in the wild, he says. Either 
we just haven't seen it, or animals can't afford to waste time preparing each 
meal. "But if [like the chimps] you have the time, you might cook all day and 
make something nice," Fernández-Carriba says. "Maybe this is one more piece 
of evidence that we are not as unique as we previously thought." 

Jonathan Knight