A team of researchers working at the Dian Fossey Gorilla Fund's Karisoke Research Center in Volcanoes National Park in Rwanda (in association with the Max Planck Institute for Anthropology and the University of Western Australia) is reporting in the journal Behavioural Processes that they have witnessed possible tool use by a mountain gorilla—it used a bamboo pole to serve as a ladder to help its offspring climb into a difficult place. This marks just the third instance of an eyewitness report of a gorilla using tools in the wild.
The famed Karisoke Research Center was established in 1967 by Dian Fossey and has been running ever since. Its mission is to study the mountain gorilla and to assist in protecting it from extinction—a dire prediction made by Dr. Lois Leaky in the early 60's after noting the declining population of gorillas due to poaching and loss of habitat. Today, researchers from all over the world come to the center to help study the wild gorillas and to learn from others that work there.
Up until now, there have been only two reports of mountain gorillas using tools in the wide (those in captivity have demonstrated a wide range of tool use). One team of researchers spied an adult pushing a stick around in a muddy part of a river to learn whether there was anything below worth trying to catch. Another team witnessed an adult move a tree-trunk crosswise over a stream then use it as a bridge to cross over.
In this latest report, team members Cyril Gruetera, Martha Robbinsa, Felix Ndagijimanab, and Tara Stoinskib report watching as a an adult female manipulated a bamboo pole to position it for use by one of her offspring, then held onto it to keep it steady as the little one clambered up the pole from the ground to join her in her perch. The team adds that it was clearly intentional as the mother didn't act until she heard distress calls from her infant.
The researchers suggest that unlike chimpanzees, which have been seen using all manner of tools in the wild to gain access to food, gorillas may be more inclined to use tools as a way to deal with the rugged environment in which they live. That suggests researchers may need to look for such use in different ways.
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More information: Behavioural Processes, Volume 100, November 2013, Pages 160–162 DOI: 10.1016/j.beproc.2013.09.006