Saturday, May 22

Two Strange Old Men

In the main troop, there are two old males called Bertrand and Chester, both of whom I've mentioned before. At first it was difficult to tell the difference between the two, as both were toothless, scarred, and shaggy. Both distinguished themselves by being friendly with the children, and occasionally, fiercely protective of the young juvenile baboons.

It was not till some time later that the two elders were able to distinguish themselves from each other. For instance, I eventually noticed that Bertrand has a little jagged fragment of canine in one corner of his mouth; it isn't completely missing like in Chester's mouth. Chester, on the other hand, is the nuclear family man, and Bertrand has a little cloud of juveniles about him most of the time, but he's not exclusive to one female.

Something else that's unclear is where these two sit in the male hierarchy. Aaron is clearly the alpha male of the troop, but no one has been able to tell who's higher up, Bert or Chester. There's also Damian to figure into the matter, who is probably sitting in the number 2 slot, above both Bertrand and Chester.

One particularly interesting morning did nothing to clear up the situation. It began the way most mornings do, the troop came down from the trees and began traveling toward a large feeding site to the north.

I'd been wondering about the relative hierarchical positions of these two for months, so when I saw Chester present to Bertrand along the path, I began to furiously take notes on the scene. These two are both quite old, each probably almost 20 years of age. Since baboon males disperse around age 7, find a new troop, and stick with that troop for the rest of their lives, these two blokes have almost certainly spent a lot of time together over the past decade. There is history here.

Right now I need to say a few words on the male-male mount, a ubiquitous dominance behavior. The smallest manifestation is the act of presentation: the dominant individual (dom) will usually be stationary (sometimes walking), and the submissive individual (sub) will stop and present its rear end to the higher ranking male. Most of the time, the lower male will quickly dart away after a few moment of presentation. However, there is a whole sequence to this behavior, which mimics the act of mating. The progression is as follows:
  1. sub male presents to dom
  2. dom will lip smack at sub
    • sub will sometimes edge closer to dom, baring teeth (another submissive gesture)
  3. if sub is close enough, dom will reach out and touch the sub, usually above the ischial callosity by the tail
  4. dom will place the other hand on sub's rump, and begin to stand and move towards sub
  5. dom assumes a standing position directly behind sub, with dom's crotch about level with sub's callosity
    • the dom might raise one foot and place it on the back of the sub's knee 
  6. dom may even give sub a few faux thrusts
At any point in the process, the sub can dart away, ending the encounter. It appears to be the choice of the sub, and probably depends on how close the two individuals are in the hierarchy, and what local condition and mood have been that day. Behaviors at the end of the chain are seen pretty infrequently, since the sub rarely let's the process progress to that point.

Getting back to Bertie and Chester - Chester presented to Bertie, complete with lip smacks. Chester just walked away after a second or two, no quick darts like one would expect to see from a submissive juvenile. Bertrand got up and followed after about a minutes. The two were at the back of the troop, but still surrounded by some females and the usual cohort of infants and young juveniles.

Well, that seemed to settle it. Chester was submissive to Bertrand. I had suspected this for a time, since while Chester is clearly larger, Bert seems to be younger, as indicated by the lone remaining canine.

I was thrown for a loop when a few minutes later, when Chester plopped himself down on a tree stump after a grueling fifty meter walk. Bertrand came walking up, slowed as he passed, and presented.

This did not seem right to me. Just five minutes earlier, Bertrand had appeared dominant, and now he was acting clearly submissive. What had changed in those five minutes? What could have changed? The two of them had been twenty meters apart, zig-zagging through the forest, occasionally foraging, seeming to be oblivious of each other.

The situation grew stranger when the behavior was repeated. Again. And Again. This continued for about two hours: every five to ten minutes, one of these guys would present to the other. There never appeared to be any pattern to the exchanges. Once or twice, the two progressed all the way to butt touching (hands only, not crotch). How intimate.

I was exasperated by these two guys. I had been meticulously observing the pair and taking notes on their behavior, but I'd no idea what to make of this interchange. I wasn't going to learn any truths about the male hierarchy; I thought I was missing several key pieces of information, and I was right. It was very interesting to watch, but at the same time, damn frustrating.

Fortunately for me, everything kicked up a notch when these two finally began a physical quarrel. I missed the outbreak, as is usually the case. I only became aware when the wahoo's and screams began. The rest of the troop took to the trees, and Aaron became alert, but did not seem involved. It was Bertrand and Chester who were thrashing around with each other in a a large thicket. They were out of sight until Bertrand followed Chester into a tree which reached above the bushes, placing them in view. The two reached the crown, continued with a few more wahoo's, and then, Chester leaped from the top of the tree, down into the bushes.

The ground was probably 20 meters below. The fight appeared to be over, and Bertrand soon reappeared. I went looking for Chester around the other side of the thicket. I found him, briskly walking away from the fight and the troop. I followed.

The old man lead me back to the troop eventually, though he took an alternate route, which I'd not seen this troop take before. After about a half an hour, Chester's meanderings return us to the body of the group, which had followed the standard path under the leadership of Aaron. Chester and Bertrand's spat was over.

As I said, I don't know what all this means. If two males had reached an equivalent level in the hierarchy, and both wanted to surpass the other, why show submissiveness? I would have expected them to awkwardly avoid and ignore each other until the tension built, and the two broke into fighting. That is, in fact, what usually happens with males. There are very few signs of the underlying struggle until the two break out into open conflict.

Tension between the two was obvious, but I was thrown off by the oddity of constant presentation behaviors, so I didn't noticed how strained their interactions were. In retrospect, the hours preceding the fight did resemble the usual pre-fight demeanors, they just had the submission displays thrown in. Were the displays not present, I probably wouldn't have noticed anything amiss before the fight. Males signals are usually very subtle, and while I have seen the signs of a fight before, most of the time I miss them.

I've pondered the events of this morning many times since, and discussed it with several colleagues. I haven't had the resources to investigate the matter thoroughly from South Africa, but when find myself with a reprieve, I'll delve into it (in the meantime, if you are curious, I recommend this paper). For the moment I'm satisfied with writing it off to the antics of two strange old monkeys who have spent way too much time around one another.

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