How do Chimpanzees Cross the Road? With All the Right Precautions

We've been told since we were in grade school (probably before) to "look both ways before crossing the street." However, it probably took a while before we remembered to do this. Chimpanzees, it seems, don't need to be reminded, as these wild animals have been observed taking the appropriate precautions all on their own when crossing many of Africa's new roadways.

That's at least according to a study recently published in the American Journal of Primatology, which details how local chimpanzee populations from the northern section of Uganda's Kibale National Park have learned to cope with the introduction of new highways.

It should be noted that past studies have looked at this behavior before, but they often involved small population sizes and narrow, unpaved roads. This new study includes observations of 122 chimps as they attempted to cross busy highways that see an average of 90 vehicles an hour - many speeding past 60 mph.

The study found that the chimps quickly learned to take on behaviors that would make any neighborhood crossing-guard proud. Researchers observed 92 percent of them looking right, left, or both ways before crossing. What's more, 57 percent of these cautious crossers also ran after making sure the coast was clear - behavior that suggests they understand the danger of lingering on a highway.

[You can watch footage of this intriguing behavior from the French National Museum of Natural History via New Scientist here.]

What was even more encouraging was that alpha males led the great majority (~83 %) of these crossings. By comparison, the same males only led about half the tree climbing expeditions in Kibale National Park's forests.

Healthy and dominant chimps also reportedly looked after the younger or injured members of the group when crossing a road, often looking back or stopping to ensure they did not trail too far behind.

Kimberly Hockings, who published a 2007 paper on the subject, found these results especially interesting, as they are very different than her own findings concerning a busy roadway in Bossou, Guinea.

She explained to New Scientist how the new study's chimps "tended to split into smaller subgroups when crossing, whereas chimpanzees at Bossou often, but not always, crossed in progression lines."

She proposed that this could be an example of how road-crossing behavior and adaptations can quickly vary depending on the traffic intensity and speed of a road. That's not unlike how a local's opinion of J-walking can change from city to city.

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