Researchers who remotely videotaped a generation of wild chimpanzees learning to use tools will gain insight into how technology was created to define human culture.
Using man-made technology of motion-activated cameras ubiquitous today, researchers who remotely watched 25 immature chimpanzees grow up have documented how mankind’s closest relatives living in the Congo Basin acquire their unique tooling skills for harvesting termites, a popular nutrient-rich one Element of the chimpanzee diet.
Unlike chimpanzees in East and West Africa, who extract termites with a single tool, chimpanzees in the Congo Basin use central Africa’s tool kits – stick sticks or perforated twigs plus fish probes – to harvest the insects from underground nests or towering mounds of earth scattered in the lowlands Woods. The chimpanzees living in this region have the most sophisticated arsenal of tool handling skills that have been documented in the animal kingdom. Not only do they use special kits of tools to harvest termites, ants, and honey, but they also customize the equipment with various modifications to improve their efficiency.
University of Miami biological anthropologist Stephanie Musgrave attempted to unravel how chimpanzees in the Congo Basin perform these complex tooling tasks, showing thousands of hours of video taping visits to termite nests, including forest elephants, leopards and gorillas in the Republic of Goualougo Triangle in the Congo. Your reward was to identify more than 660 hours of periodic visits from 25 young chimpanzees, which belong to a notoriously elusive subspecies of chimpanzees (Pan troglodytes troglodytes). This footage, recorded for over 15 years, recorded the development of their tool handling skills from birth to maturity.
In the first study to look at when Central African chimpanzees learn to use and manufacture their unique termite extraction tools, Musgrave and colleagues from the Goualougo Triangle Ape Project provide new insights into how chimpanzee cultures have persisted across generations – and possibly into the evolution of technology be the determining aspect of human evolution.
In the video above, an adult female chimpanzee and her two offspring nest after termites from an epigeal (above-ground) nest in the Goualougo Triangle, Republic of the Congo.
“Chimpanzees have the most complex tool behaviors of any animal outside of humans. So if we examine how their children mastered these tasks, we can better understand how early humans acquired complex technological skills,” said Musgrave, an assistant professor in the Department of Anthropology and Lead author of the study published in the American Journal of Physical Anthropology.
“Studying the evolution of these perishable tool kits is of particular interest as our ancestors likely used perishable tools as well – made from plants instead of stone – but these tools have not been preserved in the archaeological record,” she added.
For their study, Musgrave and her co-authors – Elizabeth Lonsdorf, David Morgan, and Crickette Sanz – conducted the first direct comparison of tool skill acquisition between two chimpanzee populations, those in Goualougo and those more than 1,300 miles to the east. in Gombe, Tanzania.
In the video above, a juvenile chimpanzee and her mother are using brush tips to extract fish probes to extract termites from an underground nest in the Goualougo Triangle, Republic of the Congo.
Lonsdorf, professor of psychology at Franklin & Marshall College, studies chimpanzees in Gombe, the oldest field study of wild chimpanzees carried out 60 years ago by renowned primatologist Jane Goodall. Morgan of Chicago’s Lincoln Park Zoo and Sanz of Washington University in St. Louis jointly founded the Goualougo Triangle Ape Project – the longest-running behavioral study of wild Central African chimpanzees – and in partnership with the Wildlife Conservation Society have had this population for more than 20 years examined. They also pioneered the use of remote video technology to study the behavior of wild chimpanzees.
For their current study, the research team adapted the methods developed in Gombe to examine the acquisition of tooling skills. And they found notable differences in the timing and order in which the chimpanzees in these two populations acquired their termite gathering skills – differences that could relate to the challenges of using and making multiple tools in Goualougo.
While infants in Goualougo and Gombe try to use tools in the first two years, Gombe teenagers learn to make their tools before or at the same time as they master them. In contrast, the Goualougo teenagers learn to fish termites before developing their tool making skills. At a young age, they usually use tools that have been discarded or transferred to other older chimpanzees.
In contrast to the Gombe chimpanzees, who use different materials, the Goualougo chimpanzees also carefully select the materials for their tools, almost always from just a few plant species. And they modify them to improve their efficiency.
Chimpanzees make these stabbing tools to gain access to underground nests. Photo courtesy Crickette Sanz
“You have a mental blueprint for the right tool for the job, and the different tool types are unmistakable,” said Musgrave. “Piercing tools are made from a species of tree that is very durable and resilient, while fish probes are made from smooth, pliable vegetation trunks. In contrast to Gombe, the chimpanzees in Goualougo fray these probes with their teeth to create a brush-like tip with which the tool catches termites ten times more efficiently. “
After Musgrave learned to make their own tools, the Goualougo chimpanzees began using them in turn – using a perforating branch plus a fish probe to harvest the termites that live in the aboveground nests and a puncturing stick plus a fish probe to extracting them from the much harder to pierce underground nests. The latter task is so arduous that researchers have predicted that it will be the last that few chimpanzees can master. You were right.
“I’ve seen chimpanzees make hundreds of attempts to break into an underground termite nest,” said Musgrave. “The ability not only requires immense strength, but also technical skills that can develop further in adolescence.”
The results underscore how life skills development trajectories can vary significantly depending on the task and chimpanzee populations with unique local cultures. In the study, the researchers note that the differences in tool traditions between locations may be related to differences in the role of other chimpanzees’ social input.
“In previous research we have documented that mother chimpanzees in Goualougo are more active and helpful than mothers in Gombe,” said Musgrave. “In Goualougo, mothers are more likely to transfer tools to their offspring. This increased support could help to acquire skills over a longer period of time. “
According to Musgrave, understanding how tool traditions are passed on and how they differ within and between species could help people understand the origins of cumulative culture during our own evolution.
“One of the main characteristics of human culture is its remarkable complexity,” she said. “Ideas and innovations pile up over time, so that new generations inherit and learn technologies that are far more complex than any one individual could invent. Comparative studies give us insights into how technology became a defining aspect of human evolution. ”
However, as Musgrave warned, the continuation and expansion of this research depends on the long-term conservation of wild chimpanzees and their cultures, which are increasingly threatened by human activities.
