In the summer 2011, I was working in Kibale National Park – a lush rainforest in Southern Uganda. Part of my PhD project involved following a group of red colobus monkeys and recording their behaviour. Red colobus are medium-sized, highly arboreal (i.e. tree dwelling) monkeys that are easily recognized by the distinctive copper cap of fur on their heads. They are unique in that they eat a diet comprised nearly entirely of leaves, live in immense groups of sometimes over 100 individuals, and are very endangered. While I’m sure it sounds glorious to go to a rainforest and follow primates, red colobus are admittedly not the most interesting monkeys. They mostly sit. Then scratch. Then eat a leaf. Then sit again. However, the monotony broke quite shockingly after I had been monitoring them for about three weeks.
Late one afternoon, as the red colobus bedded down, my field assistant and I prepared to leave the group. We had walked for less than a minute when my field assistant pointed out a small coalition of chimpanzees. I was ecstatic – seeing chimpanzees in the forest was rare, and I often did not get to stay and watch them because doing so interrupts the monitoring activities of other researchers who might be following them. This group, however, was small and un-monitored. So I stayed, took photos, and watched them until dusk approached.
What I hadn’t considered at the time was how silent the chimps had been. They might have been a few paces from the red colobus for the entire day, yet neither I nor the red colobus had known they were there.
In the morning, I returned to my red colobus group. Only, the group was behaving strangely. Despite it being a beautiful, cloudless morning, the monkeys were huddled, remaining high in the trees and in the densest foliage. After several hours of searching, it became apparent that one of the males that I had been following, among the largest member of the group, was missing. The chimps that I had been so happy to see just the day before had been on the hunt. And they had taken, and eaten, my monkey.
Chimpanzees prey on red colobus in every location where populations of the two species overlap. Indeed, red colobus compose the majority of the meat eaten by chimpanzees. I had known this. But I was still shocked to have experienced it first-hand. How dare those rotten chimps eat my red colobus!
In time, I came to realize that of the three primate species that were present in the forest that fateful evening, the only one who was behaving out of the ordinary, the only one who shouldn’t have been there, was me. The shock and sympathy I felt for the red colobus was akin to what someone might feel for an antelope taken by lions. In the natural world, there are predators and prey, and I had just witnessed the circle of life.
The first person to observe chimpanzee meat-eating was Jane Goodall in 1968. Until this time, chimpanzees were thought to be predominantly vegetarian, with the occasional smattering of insects. That chimpanzees not only ate meat, but hunted for it, opened up new avenues of research. Now, it is understood that chimpanzees tend to hunt more frequently in the dry season, when other sources of food are scarce. Hunting is also a highly coordinated behaviour that typically involves a number of chimps, including ones to chase, flush out, corner, and capture the prey. In a sense, hunting is an astoundingly sophisticated game of tic-tac-toe that requires both intelligence and cooperation. Being a cultural activity, chimpanzees in different locations will have different methods of hunting. Once the prey has been caught, who gets the meat and who doesn’t is central to affirming the organization and cohesion of the group.
Not only is chimpanzee meat-eating relevant to understanding their behaviour and ecology, it is key to understanding our own history. Both humans and chimpanzees hunt for meat, suggesting that doing so is evolutionary – a primitive trait that was inherited from the ancestor of chimpanzees and humans. If this is indeed the case, human desire for meat to supplement our diet is a tendency that is millions of years old, as is our inclination to hunt for it, rather than scavenge. Research on chimpanzees has also given us clues on why we cook our food. Surprisingly, chimpanzees also prefer their meat cooked! While in the wild it is eaten raw because they have not developed the propensity to create fire, feeding experiments undertaken on captive chimps show that given the choice, they will take boiled cubes of meat over raw, presumably because they are soft and easier to chew. This suggests that the desire to eat cooked meat arose before our ancestors had ever managed to produce fire.
Although my initial reaction to chimpanzee meat-eating was grim, it was this experience that led me become actively involved in chimpanzee conservation. Chimpanzees are just like us – all the way down to their taste in food. Research on wild chimpanzee behaviour is of crucial importance because chimpanzees are in many ways a reflection of our historic selves. I believe that chimpanzees are worth saving because they are beings that are part of this planet, and inherently deserve the freedom to live in the wild and share the earth as much we do. But if you need more of a reason, eliminating chimpanzees from the wild would sever a link to our own history. They are our closest relative, and in understanding them, we gain insight into where we came from.