In my last column, I briefly introduced you to the idea that, contrary to popular belief, aboriginal hunting is not inherently an effort in true conservation. However, there are many factors to consider when evaluating hunting as a conservation tool, aboriginal efforts or otherwise. I said I would offer an example….so let’s go back to Africa and talk data!
My primary research while in graduate school was focused on something ethnoarchaeology. I’ll spare you the complete Anthropology 1 lecture on what it is, but for my current discussion suffice it to say it is living with a group of people to observe them and understand how they create potential archaeological sites on the landscape…. which introduced me to the Hadza people of Tanzania.
Let me give you some basics (don’t worry if you’d like to hear more; we’ll explore additional details of the Hadza in future columns). The Hadza are hunter-gatherers, which means they hunt wild game and gather wild plants for their subsistence. They don’t grow their own food, herd domesticated stock or buy food for consumption (however, they do trade for meat occasionally – the first rule of anthropological observation: everything has an exception!). They hunt with bows and poison-tipped arrows and take game that ranges in size from dik-diks (collie-sized antelope) to giraffe. Finally, for purposes of this discussion, you also need to know that they use two general methods of hunting strategy. One is to ambush game from blinds near waterholes (like archery hunters setting up blinds or deer stands near a game trail). The second strategy, essentially in play everytime a Hadza hunter leaves the village, is to look for, identify and stalk game for a closer shot. We call this “encounter hunting” and it’s what most of us do on a regular basis during deer season.
My research was primarily focused on determining age and season of death of game animals taken by the Hadza. I accomplished this by sectioning teeth from their kills so that I could read the “rings” in the teeth roots. Basically, mammal teeth develop rings in their teeth similar to what you would see in a tree stump after you cut it. Like trees, counting the total number of rings in the teeth yields the animal’s age at death; however, the rings also form seasonally, and so the time of year that an animal was killed is also revealed. Of course, this is a laboratory process, and in the field I was doing the initial collection of teeth samples from observed Hadza kill sites, but also from abandoned Hadza camps where season was unknown.
Although I was observing Hadza hunting behavior, methods and success rates, at the time it wasn’t my primary focus. Besides we had all read James Woodburn’s account of the Hadza from decades earlier and had what we thought was a pretty good description of Hadza hunting practices. In particular, Woodburn noted that Hadza employ very conservation oriented strategies of taking game, particularly when hunting zebra, which were killed more often than other animals. Specifically, they appeared to concentrate on taking males, suggesting that the Hadza were indeed trying to manage the population for long term yields. This was certainly in keeping with what we were taught about aboriginal hunting; that there was an intentional effort to conserve game species by taking individuals contributing the least to the overall reproductive health of the population (sorry guys…you don’t need many males to maintain reproduction rates in a population of females – in the evolutionary scheme of things, we are far more expendable than ladies!).
Back at the lab, the data appeared to confirm what Woodburn had suggested. When I looked at kills from dry season encampments and kill sites, there was indeed a significantly greater proportion of male zebras in the assemblages. Moreover, the ages of these animals tended to exceed 5-6 years of age. This is important because that is the approximate time at which dominant males (who have control of female harems) start getting usurped by younger, stronger males who take over the herd. So, not only were Hadza apparently killing mostly males, but they were also taking males that were generally beyond effective breeding age. What could be a clearer example of an aboriginal conservation strategy?
The problem came when I looked at samples from kills taken at other times of the year (an important point: the dry season is only about 3-4 months in duration). Data from those animals did not match the dry season pattern. Males, females, old and young were taken pretty much at random throughout these seasons. There was no obvious pattern either in age or sex of zebra taken outside of the dry season.
So what the hell was I missing?
Tune in next week to find out…..