FYI.

This story is over 5 years old.

Tech

How a Ragged Band of Chimpanzees Survives on the Edge of Human Civilization

As humans encroach, the battered chimps have turned to night raids on farms to find food to live.

For the first time, researchers have filmed the nighttime activities of chimpanzees living on the edge of the Kibale National Park in Western Uganda, an area shared by humans and apes. What they found was unsettling. The chimpanzees, previously thought to be most active during the day, had adapted to a life of tense, night-veiled raids in human territory.

Human expansion into areas occupied by non-human animals is usually accompanied by a host of destructive practices: deforestation, poaching, and the decimation of food sources and entire species. Such activities force the creatures that live in these regions to survive and coexist in new and often troubling ways. In their disturbed habitat, the apes of the Kibale forest have no choice but to cross into human territory and steal crops under the cover of night, and often at great peril.

Advertisement

According to the researchers' study, published today in PLOS One, the raids are carried out by groups of apes—males, females, and clinging infants alike—many of whom had been severely scarred or maimed by poachers' snares. Crop fields are guarded day and night in the area, and the researchers reported local anecdotes of apes being killed for trespassing. Naturally, this made nighttime excursions into human territory a tense venture for chimpanzees.

"Before entering the field, chimpanzees displayed scanning behaviours and some individuals were not entering the field, staying at the edge," the authors wrote. "While in the maize field, chimpanzees were sometimes chased by barking dogs or run after by the guardian of the field, who threw a branch towards a severely mutilated adult female who hurried to cross the bridging tree."

To capture the raids, the team—led by Sabrina Krief of the National Museum of Natural History in Paris—set up camera traps around the edge of the Kibale National Park during a period of maize crop maturity. Over the next two weeks, the researchers identified 72 apes out of the 80 estimated to be living in the area by the Sebitoli Chimpanzee Project, which has been monitoring the chimpanzees' daily activities in the park since 2009, although its data remains unpublished.

According to the report, the raids themselves weren't the only indicators of how humans have disturbed the habitat of the chimpanzees in the region surrounding the forest. The raiding parties consisted of upwards of eight chimpanzees, more than double the party size of normal feeding activities in the forest. Moreover, of the 72 identified apes, 26 displayed scars and limb deformities from hunters' traps, and eight were missing limbs.

According to the researchers, their study is the first to document the creative, adaptive, and at times risky behaviour of apes surviving at the edge of human civilization. While the two-week filming period is likely too short to generalize the results to other areas and ape populations, the authors write that their study should be impetus to further document the uncommon and unexpected activities of non-human animals existing in a world becoming increasingly inhospitable to their way of life.