This caught my eye
Chimps are exceptionally cautious when they cross the road. Ninety-two per cent of them looked right, left, or both ways before or during crossing, and 57 per cent ran across – showing that they knew the value of reaching the other side as quickly as possible.
Alpha males led and organised 83 per cent of the road-crossing posses, compared with only 51 per cent of tree-climbing expeditions in the forest studied in parallel. This implies that they recognised the importance of extra vigilance during road crossings.
There was also evidence that healthy and dominant chimps often made sure that stragglers or more vulnerable members of the group crossed safely. Some 86 per cent of the healthy chimps looked back or stopped when at least one vulnerable individual, such as an infant or injured chimp, trailed behind.
Chimps behaved differently crossing a quiet road in an earlier study in Bossou, Guinea, led by Kimberley Hockingsof the Centre for Research in Anthropology in Lisbon, Portugal.
“At Sebitoli, chimpanzees tended to split into smaller subgroups when crossing, whereas chimpanzees at Bossou often, but not always, crossed in progression lines,” says Hockings. “This might be down to a higher intensity and speed of traffic at Sebitoli, forcing chimpanzees to split up.”