Elephants never forget... to avoid the full moon

Published: 23 July 2013 at 15:29

Anglia Ruskin research shows influence of lunar cycle on their foraging tactics

A new study has shown that the night-time foraging behaviour of elephants changes during the lunar cycle – to help them avoid contact with humans.

The research, conducted by scientists at Anglia Ruskin University, has just been published by the African Journal of Ecology.

The scientists carried out their work in and around the Mikumi National Park in Tanzania, approximately 185 miles west of Dar es Salaam.  The national park is part of the Mikumi-Selous ecosystem, which holds one of the largest populations of wild elephants in Africa.

Five villages bordering the park’s northern boundary were selected for the research, which recorded instances of elephants raiding crops being grown close to and within human settlements.

The study 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.

Co-author Dr Rachel Grant, Lecturer in Animal Behaviour at Anglia Ruskin, said:

“Our results support the belief that elephants alter their behaviour to reduce the risks of encountering 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.
“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 behaviour during the lunar cycle and explain why elephants are less likely to venture close to villages during the full moon.
“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.  Many animals alter their behaviour according to varying light levels and the perceived risk of predation, and this is likely to be a partly evolved, partly learned response.
“This evidence of avoiding the full moon is likely to be a feature of elephant behaviour in other populations outside of Tanzania and, importantly, could be used to provide information to help protect people’s farms from the extensive damage these animals can cause.”

The research was led by Dr Jody Gunn, a former PhD student at Anglia Ruskin and now Senior Planner for the Parks and Wildlife Commission of the Northern Territory in Australia.  The project was funded by the Darwin Initiative for the Survival of Species and Anglia Ruskin’s Animal and Environmental Research Group.