Another aspect of this semester long blogging experience is getting my students to share their passion for the research that they do. This week we’re hearing form Allison Roth and her work on intergroup conflict in Blue Monkeys

Intergroup Encounters in Blue Monkeys

By: Allison M. Roth

In the Kakamega forest, sunlight glimmers through the canopy, dancing on my face like lightning bugs flickering at dusk. The lush greenery surrounds me in in a delicate blanket of foliage as I listen to the quiet rustle of the leaves. Sitting here, it is easy to feel like I am the only person left on earth. The air seems fresher, the skies clearer, and I cannot imagine a more beautiful place. The call of a blue monkey rings through the air. But wait!! That is not the call of a friend, but rather, it is one of an enemy. An epic battle is about to ensue. Dun dun dunnnnn. Ok, ok perhaps I am being overly dramatic here. Blue monkeys are actually a fairly peaceful species of primate. However, just as humans wage wars against one another for access to food, water, land, etc., these monkeys fight with each other for important resources that they need to survive and reproduce.

Blue monkeys are a species of primate that is native to Central and East Africa. They are large bodied monkeys who, contrary to their name, possess a grayish colored fur. Blue monkeys typically form groups consisting of 10 to 50 individuals. Although there is very little conflict between individuals of the same group, members of a group will band together to defend their territory from other groups. Territories contain resources such as food, sleeping sites, mates, and refuges from predators that are essential to these creatures’ wellbeing.

Intergroup encounters in blue monkeys occur when two groups can see or hear one another. In the Kakamega forest, most intergroup encounters involve unfriendly exchanges between the two groups. During these intergroup encounters, one might witness the monkeys making aggressive vocalizations towards one another, individuals lunging at or chasing each other, and animals engaging in violent physical contact. Unlike humans who readily slaughter their enemies in times of war, in blue monkeys it is extremely rare that violence escalates to levels that result in the demise of one or more individuals.

A group is considered to have won an intergroup encounter when the other group flees. In some primates, the winner of an intergroup encounter is always the group containing the greater number of individuals. In other species, the winner of an intergroup encounter is always the group that owns the territory in which the intergroup encounter occurs, regardless of the relative sizes of each group. Lastly, there are some species in which the winner of an intergroup encounter is determined by a combination of the two aforementioned factors.

It may seem surprising that smaller groups are able to defeat larger groups during intergroup encounters, but there is a sound explanation for this phenomenon. Groups gain information about an area with repeated use of that area. This knowledge may make it easier for individuals to find food or hide from predators. Because a group uses its own territory more frequently than any other group, the owners have more knowledge about their territory than other groups. This knowledge causes a territory to be more valuable to its owners than it is to any other group. Individuals are willing to take more risks when fighting over a resource that is of greater importance to them. This increased willingness to take risks confers an advantage to the owner of a territory, resulting in groups winning intergroup encounters that occur within their own territory.

My research aims to determine what factor/s decide the outcome of intergroup encounters in blue monkeys. I have several other questions that I will be asking that are along the same lines, but in the interest of giving my readers something to look forward to, I will not disclose these as of yet. However, please feel free to contact me at [email protected] with any questions you may have about blue monkeys or intergroup encounters in primates.