Wild chimps are using the cover of darkness to disguise their nighttime antics, which consists of raiding nearby farmland for crops, according to new research.
Camera traps caught the chimpanzees in the act, providing the first record of "frequent and risky" nocturnal raids to find food," according to the research team.
They think that nearby human activities encroaching on chimp habitats may be causing the animals to become emboldened and more daring than scientists suspected.
To better understand how these night raiders are adjusting, researchers set up camera traps in Kibale National Park in Uganda.
"[It's] surrounded on the outside by smallholder farms, forest fragments and tea estates," the authors wrote in their paper, published in the journal PLOS ONE.
During the 20-day study period, researchers recorded a total of 14 crop-raiding events, with groups of about eight chimpanzees taking part in each raid. The intrepid incursions even included vulnerable animals, such as females with clinging infants.
They would raid during the day as well, but during night-time raids the chimps stayed longer in the maize fields. They also showed fewer signs of vigilance and anxiety, such as looking around or scratching themselves roughly, which are signs of stress.
These raids, which were far more daring than researchers anticipated, are most likely driven by habitat loss, a bigger threat to the chimps than natural predators.
"It forces chimps to explore new food sources, like human crops," Dr. Catherine Hobaiter, an expert in chimp behavior from the University of St Andrews, told BBC News.
"Raiding fields is extremely dangerous - chimps may be attacked or even killed by people defending their crops, but by raiding at night [these chimps] seem to have reduced this threat."
While the change in behavior is certainly effective, such drastic measures are worrisome to scientists. According to Hobaiter, the fact that these wild animals are willing to go to such lengths to acquire foods means they're under real environmental pressures. It also increases the chances that there will be run-ins with humans trying to protect their crops.
"From a conservation perspective, the only long-term solution is the protection of the remaining forests," she added.
[Credit: PLOS Media via NewsInFollow]