A team of scientists from The University of Western Australia have found the first evidence that chimpanzees remember the landscape of their rugged, mountainous habitat and use this recall to choose the best route to their next meal.
The study, published in Current Biology, found that a chimpanzee’s memory is so precise, that they select routes across ridge tops and valleys, as well as hiking trails, in a way that closely matches routes predicted by computer models.
Dr Samantha Green from UWA’s School of Human Sciences was studying the behavioural ecology of chimpanzees in the mountainous Nyungwe National Park in Rwanda when she observed that chimpanzees seemed to know the location of the nearest hiking trails and ridge-lines well in advance of the research team.
"Variable landscapes are costly to traverse, placing a premium on individuals that can plan efficient routes."Dr Samantha Green
Dr Green followed the chimpanzees for 14 months to chart the routes taken by the chimpanzees.
Using a predictive model that determined the path of least resistance, Dr Green worked with researchers from the University of Lethbridge to compare this with the routes the chimpanzees took through the rugged forest.
The model included features that impede animal travel, such as slope and vegetation cover and assumed the chimpanzees had full knowledge of their environment.
The results showed that chimpanzees seem to have a detailed knowledge of the mountains and hiking trails in their habitat and use this knowledge to take the most efficient routes between food sources.
The ability could be a key trait that has enabled chimpanzees to maintain their energy balance in a low-resource environment.
Dr Green said the need to remember and find fruit trees has long been thought to be a key driver in the evolution of sophisticated primate brains and ‘harsh’ landscapes may also play a role.
“Variable landscapes are costly to traverse, placing a premium on individuals that can plan efficient routes,” Dr Green said.
“Future research on the cognitive abilities used by chimpanzees and other large-brained animals to navigate a variety of landscapes is needed to shed light on the role energy landscapes play in shaping animal cognition.
“Continued advances in GPS and drone mapping technologies offer exciting opportunities to test this ability on other animals in a variety of environments.”
Study co-author Dr Cyril Grueter said prior to the study not much was known about how chimpanzees cope with the challenges posed by living in rugged, high-elevation environments.
“Chimpanzees are our closest relatives in nature and can offer valuable insights into the evolution of our own behaviour,” Dr Grueter said.
The study has been endorsed by the Rwandan Development Board.