Central African chimpanzees crave honey so much that they've invented the animal kingdom's most complex known set of tools to get it, according to researchers who found many of the tools still slathered with the syrupy liquid.
A new study on the findings, accepted for publication in the Journal of Human Evolution, is believed to be the first to compare such a sophisticated chimp tool set with Stone Age human technologies. Hunger for honey appears to have motivated both species.
"Tools are used to solve ecological challenges," lead author Christophe Boesch explained to Discovery News. "The more complex and rewarding a challenge is, the more complex the solutions are going to be."
Boesch, who is the director of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology, added that Central African tropical forests are full of bees and their honey, so "humans and chimpanzees living in such an environment would face similar challenges and, with both having extended learning abilities, would rely upon tools to overcome the challenges."
For this latest study, however, Boesch and colleagues Josephine Head and Martha Robbins observed chimpanzees at Loango National Park on the coast of Gabon, Africa. They identified at least five different types of chimp-made honey extraction tools used in sequence.
The tools consist of pounders, enlargers, collectors, perforators and swabbers. Chimps, suspended in acrobatic positions on branches, might first pull out a thick stick pounder to break open beehive entrances. They then reach for another stick, the enlarger, to perforate and widen different honeybee hive compartments. Next comes the collector, used to dip or scoop out honey.
Different tools and methods are needed to obtain underground bee honey. The chimps wield a perforator to penetrate the ground, locate a honey chamber and dig into the soil. They then pull off strips of bark to "dip and spoon the honey out of the opened beehive."
Obtaining honey from an underground hive isn't easy. Aside from dealing with angry, stinging bees, the chimps must dig narrow sideways tunnels, maintain perfect aim and prevent soil from falling into, and ruining, their desired sweet reward.
Boesch and his team believe the chimps must therefore possess "an elaborate understanding of unseen nest structure, combined with a clear appreciation that tools permit the location of unseen resources, and a precise three-dimensional use of geometry for reaching the honey chamber from the correct angle."
The chimp discoveries come on the heels of a recent study on captive rooks, a member of the crow family. These birds make and modify tools, such as bended hooks and stone catapults, using at least two such tools in a sequence.
"This finding is remarkable because rooks do not appear to use tools in the wild, yet they rival habitual tools users such as chimpanzees and New Caledonian crows when tested in captivity," said University of Cambridge researcher Chris Bird, who led the avian project.
Boesch was pleasantly surprised by the rook ingenuity and agrees that tool know-how isn't restricted to humans and our closest living primate relatives.
He added, "What seems so special in humans and chimpanzees is the ubiquity of tool use — seen in all studied populations of each species — and the flexibility of the techniques."
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