African elephants appear to use the cover of darkness to avoid being detected by humans when raiding farmlands for food, according to a new study
The study also showed that the elephants even adjust their foraging with the lunar cycle, which also is believed to be a way of avoiding contact with humans.
"Elephants are cathemeral, meaning they are active during day and night, but raid crops almost exclusively at night, suggesting they only venture close to villages when they believe they are harder to detect,” said Dr. Rachel Grant a lecturer in animal behavior at Anglia Ruskin University in England.
She added that an elephant's awareness of the higher risk of being detected on moonlit nights, because of the visual advantage gained by humans, could account for the changes in their behavior during the lunar cycle and explain why elephants are less likely to venture close to villages during the full moon.
The study was carried out in an around Mikumi National Park in Tanzania, about 298 kilometers west of Dar es Salaam, which holds one of the largest populations of wild elephants in Africa.
Researchers selected five villages near the park and recorded the instances of elephant crop raiding. They found that the number of elephant "raid nights" varied throughout the lunar cycle, with significantly fewer raids occurring during a full moon. The extent of crop damage also fell considerably during the full moon phase.
"Some animals that vary their activity according to the lunar cycle have an internally arising biological rhythm; alternatively they may be basing their decision-making on local conditions at the time,” said Grant. “Many animals alter their behavior according to varying light levels and the perceived risk of predation, and this is likely to be a partly evolved, partly learned response.”
Grant said the behavior was likely to be found in elephant populations outside Tanzania, and that the information from the study could be used to protect farms from elephant damage.