The modern hazard of crossing the road has revealed an unprecedented chivalrous streak among wild chimpanzees, according to video footage released yesterday.
When faced with a busy road, large male chimps headed to the front of the pack to check the road was clear before leading females and their young across. Meanwhile, other males headed to the back of the group to bring up the rear. Often, a high-ranking male assumed the role of lollipop man by wandering on to the road and checking it for traffic until the entire pack had crossed safely.
Experts in animal behaviour recorded the extraordinary footage while filming a mixed group of 12 chimps in Guinea, western Africa, as they negotiated two roads that ran through their territory. One road was a simple mud track used as a path by local pedestrians, the other had recently been widened to carry trucks, cars and motorbikes.
The footage, amassed over three months, shows the pack of three adult males, five adult females, three younger chimps and one infant, crossing the roads near the small town of Bossou to reach foraging grounds on the other side.
On each crossing, Kimberley Hockings at Stirling University and Tetsuro Matsuzawa at Tokyo University noted the position of the alpha male, Yola, the secondary male, Foaf, and the lowest-ranking male, Tua. They found that Yola was most often at the back of the pack, with leading or lollipop duties designated to the other adult males.
To test the effect of traffic, the researchers timed how long the chimps paused prior to setting out across each road. Before crossing the smaller road, the group waited an average of 24 seconds, but waited three minutes before choosing to cross the main road and waited longest if there was more traffic using the road.
