Chimps use 'specialised tool kits' to catch army ants

Washington, September 3 (ANI): A new study has shown that chimpanzees in Congo use "specialised tool kits" to catch army ants.

Published in the American Journal of Primatology, the study suggests that chimpanzees have developed a 'sustainable' way of harvesting food.

Led by Dr Crickette Sanz, researchers associated with the Goualougo Triangle Ape Project studied several communities of chimpanzee throughout the Nouabale-Ndoki national park in the Republic of Congo.

After spending a collective 111 months in the Goualougo Triangle, the researchers recovered 1,060 tools, and collected 25 video recordings of chimpanzees using them to forage for army ants.

"The use of tool sets is rare and has most often been observed in great apes. Until now there have been no reports of regular use of more than one type of tool to prey upon army ants," said Sanz.

Chimpanzees are already known to use tools when foraging for honey or collecting termites, but the variation in techniques and their relationship with the ants has perplexed scientists for decades.

"In other studies, based across Africa, chimpanzees have been seen to prey on army ants both with and without tools, and it was inexplicable why some chimpanzees used different techniques to gather the same prey," said Sanz.

The team revealed that 36 per cent of sets recovered by them contained two types of tools, nest perforating tools and ant-dipping probes.

The chimpanzee inserts a an ant-dipping probe into a nest or column of ants and gathers the individuals who stream up the tool.

The perforating tools, on the other hand, are used to open nests so the chimpanzee can gather the ants within.

The rsearchers admitted that the tools observed during the present study were similar to other recorded tools, but added that their findings suggested that chimpanzees were selecting tools depending on the characteristics of the ant species they are foraging.

Chimpanzees that harvest ants simply by raking a nest open with their hands cause a massive counter-attack from the ants, and this also results in the ants to migrating and building a new nest at a different location.

However, by using the perforation tools the chimps can entice the ants out and can allow the insertion of the second tool for dipping.

This not only reduces the ant's aggressive behaviour, but may also be a "sustainable harvesting" technique because the ants will stay in that location allowing the chimpanzees to revisit this renewable source of food.

"It has only recently been discovered that these particular chimpanzees use several different types of tool sets which could be their cultural signature of sorts. There is an urgency to learn about these behaviours as the existence of the apes in the Congo Basin is threatened by commercial logging, bushmeat hunting, and emerging diseases," concluded co-author Dr. David Morgan. (ANI)