A scream breaks the savannah dawn, followed by more screams and the rustle of branches: wild Fengori chimpanzees are saying good morning to each other in the dry, rugged Sahel region.
The rare chimpanzees, who live in the hot scrubland of southeastern Senegal rather than in the more common forests, exist at the extreme edge of what is possible for their species.
Their unusual lifestyle offers clues to humans’ own evolutionary history, and their adaptation to the heat is timely in a world with rising temperatures.
Soaking in pools, cooling off in caves, even wielding spears: the 35 wild chimpanzees of the Fongoli colony have adapted to an environment that goes against the traditional norms of their species.
Now, 25 years after primatologist Jill Pruetz began groundbreaking research on Savannah chimpanzees she had never been accustomed to observing, she has a wealth of data.
The long-term nature of this study allows us to gain a deeper understanding of the Fongoli community’s behaviour, relationships and the way they learn from generation to generation.
“We only knew chimpanzees from forest areas until they became accustomed to observers so that we could track them and get data,” Pruetz told AFP. Pruetz spent two days following her and her team as they tracked the primates through the jungle.
The Fongori chimpanzees live in a home range of 100 square kilometers (40 square miles) and are the only group of savannah chimpanzees in the area, but the only ones studied for many years.
On a recent morning, AJ, Rafi, Diouf and the ambitious young Pistachio sat atop a baobab tree, plucking their breakfast fruit and cracking the fruit by tapping on the branches.
They use screams or “gasps” to communicate with other members nearby.
Pruetz and her team of Senegalese researchers track the adult males of the group (currently numbering 10), selecting one each day and tracking them from dawn to dusk. However, to make the females more wary of poachers, they are not followed.
There is a strict hierarchy of males, from Cy to Siberut. Although Siberut has superb hunting skills, it is the oldest and lowest caste.
Because social apes spend most of their time together, Pruetz was still able to observe females and their pups.
It turns out that the females are the most pioneering members of the clan: they are the only non-human animals to systematically use tools for hunting.
Pruetz and her researchers have observed this behavior nearly 600 times.
-“Most Popular Areas”-
The females usually hunt bush pups during the rainy season after shaving sticks into spears with their teeth, impaling the young primates when they hide in tree cavities.
During the hot season, with heat indexes reaching as high as 49 degrees Celsius (120 degrees Fahrenheit), life on the savannah can be very difficult.
Fongori chimpanzees “have to cope with the hottest areas we’ve ever studied chimpanzees,” Pruetz said, and must “minimize energy expenditure” during the dry season.
They are the only wild chimpanzees in the world known to dip in natural pools. They also “used caves to rest because they are cooler,” Pruetz told AFP.
The savannah woodlands of the Fongori chimpanzee habitat are similar to those in which our ancestors lived six to seven million years ago.
Pruetz said that by looking at chimpanzees (both chimpanzees and bonobos are our closest living relatives), perhaps we “can help corroborate some hypotheses about the behavior of those true early humans or bipedal apes.”
While many of the Fengori chimpanzees’ adaptations mean they can cope with “high heat stress,” Pruetz said, “we’re not sure they can continue to do that as climate changes.”
– gold rush –
Fungori apes are members of the critically endangered subspecies of West African chimpanzees.
While they have traditionally co-existed with humans in their habitat, a new threat has emerged: the gold rush leading to an increase in artisanal and industrial mines.
In the morning, before the savannah fauna begins its daily chorus, the rumble of rock grinders crushing buckets of substrate can be heard.
A fire breaks out in an artisanal mine and guards guard the equipment at night.
Landmines could mean water contamination, greater resource extraction and the spread of human diseases to chimpanzees.
Papa Ibnu Ndiaye, a wildlife researcher and professor at Dakar’s Cheikh Anta Diop University, said studying Fengori chimpanzees would allow “local authorities to obtain accurate information to make informed decisions about protecting Senegal’s biodiversity.”
Pruetz spends part of each year teaching at Texas State University while her four research assistants and project managers from nearby villages continue to track the great apes.
When Rafi tapped a baobab fruit eight times, they kept count, or noted which arm he used—even though chimpanzees are typically left-handed.
But they also carefully tracked chimpanzee friendships and social dilemmas.
“When someone comes home from a long day with chimpanzees, what drama do you sit around the dinner table and talk about? What did Cy do today? What did Pistachi do today?” said Pruetz, who has images of three deceased or missing members of the chimpanzee group tattooed on her arm.
Chimpanzees can live up to 50 years in the wild, and how their relationships change is just one of Prutz’s many interests.
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