Chimpanzees Hunt for Specific Tools When Extracting Aggressive Army Ants for Food

It turns out that when it comes to eating ants, chimps prefer specific tools. Scientists have now taken a closer look at West African chimpanzees and the tools that they use when extracting aggressive army ants for food.

The chimps use a technique called "ant dipping" when it comes to retrieving ants. First, they dig out a nest with one of the thicker shoots from a particular spindly plant, which aggravates the insects. Then, the chimps dip a second tool, a more slender shoot, into the nest. This causes the ants to swarm up the shoot. One the slender shoot is covered with ants, the chimps pull it out and then wipe their fingers across it, scooping up ants before popping them in their mouths.

"Ant dipping is a remarkable feat of problem-solving on the part of the chimpanzees," said Kathelijne Koops, one of the researchers, in a news release. "If they tried to gather ants from the ground with their hands, they would end up horribly bitten with very little to show for it. But by using a tool set, preying on these social insects may prove as nutritionally lucrative as hunting a small mammal-a solid chunk of protein.

In order to learn a bit more about this technique, and see how chimps acquire knowledge to do it, the scientists set up cameras to take video footage of chimps. Previous studies have shown that chimpanzees will actually select longer tools for faster, more aggressive types of army ants.

"Scientists have been working on ruling out simple environmental and genetic explanations for group differences in behaviors, such as tool use, and the evidence is pointing strongly towards it being cultural," said Coops. "They probably learn tool use behaviors from their mother and others in the group when they are young."

The findings reveal a bit more about chimp behavior. More specifically, it shows how chimps have the ability to learn from one another and pass down social behaviors.

"By studying our closest living relatives we gain a window into the evolutionary past which allows us to shed light on the origins of human technology and material culture," said Koops.

The findings are published in the American Journal of Primatology.