Wild chimps in Uganda have learned to look both ways before crossing roads

Chimpanzees face daily a dangerous situation and it’s not just from poachers but a high-traffic asphalted road in the Sebitoli area of Kibale National Park, Uganda

Infrastructure is big business throughout Africa with roads being built to support regional development, industry, and tourism.

But few studies have examined the effects of all the infrastructure on animals and until now there hasn’t been many looking into how wild animals adapt their behaviour and ecology in road-forest ecotones.

A new study from French and Uganda researchers have studied how chimpanzees behave while crossing the road.

Previously, studies have demonstrated the chimpanzee’s ability to adapt in anthropogenic landscapes but until now none have examined the effects of asphalted highways on wild chimpanzee behaviors.

122 crossings by chimpanzees studied

Over a 29-month period, the chimps were surveyed as they assessed the dangers posed by an asphalted road crossing the Sebitoli area of Kibale National Park in Uganda.

In total, the researchers led by Marie Cibot of the Muséum national d’Histoire naturelle in Paris, 122 individual chimpanzee crossings were studied.

Although the asphalted road represents a substantial threat to crossing animals (89 motorized vehicles per hour use this road and individuals of six different primate species were killed in 1 year), chimpanzees took into account this risk.

More than 90% of the individuals looked right and left before and while crossing.

Here’s what else they found

  • Chimpanzees crossed in small subgroups (average 2.7 subgroups of 2.1 individuals per crossing event).
  • Whole parties crossed more rapidly when chimpanzees were more numerous in the crossing groups.
  • The individuals most vulnerable to the dangers of road crossing (females with dependents, immature, and severely injured individuals) crossed less frequently compared with non-vulnerable individuals (lone and healthy adolescents and adults).
  • When crossing in a group, many chimps watched and waited for other members of their party before continuing over to the other side.

Healthy males often led crossings

Moreover, healthy adult males, who were the most frequent crossing individuals, led progressions more frequently when crossing the road than when climbing or descending feeding trees.

Almost 20% of the individuals that crossed paid attention to conspecifics by checking on them or waiting for them while crossing.

What does all this observation tell us? It tells us that chimpanzees can adapt behaviour based on human-impacted habitats.

It also reveals that with all the chimps crossing that road, there should be mitigation measures such as bridges, underpasses, reduced speed limits, speed-bumps, signposts or police controls.

h/t: New Scientist, American Journal of Primate

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