Chuck Bednar for redOrbit.com – @BednarChuck
While chimpanzees and bonobos are closely related to one another, the two species differ significantly in terms of their predisposition for tool use, according to new research published Tuesday in the journal Scientific Reports.
Humans are kings of the tool-using primates, the study authors explained in a statement, with chimps following closely behind in terms of the diverse ways that they use implements to help them perform various tasks. For instance, they use sticks to help catch ants and termites, stones to crack nuts, and various other tools to groom themselves and communicate.
Bonobos, on the other hand, rarely use tools for any reason and never use them when foraging for food, the researchers added. In the new study, Dr. Kathelijne Koops from the University of Zurich and the University of Cambridge, and colleagues from Kyoto University in Japan, set out to analyze this phenomenon and learn how humans may have emerged as the ultimate tool user.
Bonobos may have lost the predisposition for tool use
Dr. Koops and her fellow investigators tracked communities of wild chimpanzees and bonobos in Uganda and Congo over a period of several months, cataloguing all instances of tool use and all potential opportunities for tool use based on different environments and other factors.
They hoped to solve the mystery of how exactly a primate becomes a tool user by investigating if it has to do with the environment where the apes live and the opportunities it has for tool use. They also looked to see if it had more to do with learning how to use tools from other apes or if it is something deep within the primates themselves – an intrinsic, innate propensity for object manipulation.
“Chimpanzees and bonobos differ in their predisposition for tool use, which does not mean that the ability to use tools is innate,” Dr. Koops told redOrbit via email. “Both species are able to use tools, and even young chimps need to learn from others how to use tools. The difference lies in the intrinsic motivation to use tools, or their ‘object-orientedness.’”
“We propose the hypothesis that bonobos may have lost the predisposition for tool use,” she added. “The question is indeed why. A recent study on captive apes using eye-tracking techniques found that bonobos pay more attention to social cues, whereas chimpanzees pay more attention to objects. Together with our findings this suggests a possible trade-off between tool use motivation and social attention. In bonobos, selection pressures may have been stronger on social skills, and in chimpanzees tool use skills may have been more important.”
First inter-species tool use comparison
The study, which the authors describe as the first inter-species comparison of tool use in the wild ever completed, found that environmental opportunities did not explain the differences between chimps and bonobos when it comes to tool use, as the latter had access to just as many tools and foraging opportunities in their habitats than the chimpanzees.
Likewise, social opportunities did not play a role, as young bonobos actually spent more time with their mothers and had more individuals in close proximity for longer periods of time when feeding than young chimps. However, immature chimpanzees were found to be more likely to manipulate and play with objects on their own than young bonobos.
“Given their close evolutionary relationship with humans, insights into the tool use difference in our closest living relatives can help us identify the conditions that drove the evolution of human technology,” Koops added.
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