Troop Mind Journal 03/05

The troop was sleeping in one of the usual spots, a spot which was once a favorite of the second troop, and effectively ceded by tr.2 to tr.1 during the summer months. Now the first troop sleeps there more often than any other site, which is of little surprise given the proximity of the site to the ripe feeding grounds.

On a very ordinary day, the group would lazily travel a short distance through small valley and field to the grounds, stopping a few times to groom or look out for signs of other baboons. There are a few small variations on these very ordinary days, but all ultimately end the same.

An exception occurred early one morning when the animals came down from their roost in the trees. Instead of crossing the valley which lay between the monkeys and the feeding grounds, the young males set out in the opposite direction, up the mountain, away from the feeding grounds. I expected them to come back to the main sleeping site, but they never did. They continued up the mountain, and the whole troop followed them.

I didn't hear any distant baboon sounds that would have indicated the presence of another troop, but of course, my ears are not tuned to perceive baboon vocalizations and on an absolute scale, my sense of hearing is not as powerful as a baboon's. So maybe Tim Curry's troop was sitting just on the other side of the ridge, or further up the mountain, and the troop was responding to their presence.

If this were the case, we would have expected the young males to act as they did, but after a short time, these males retreat to the core of the troop, and the day continues almost as if there was no disturbance. This is a grossly simplified version of what I see, yet these troop movements seem to defy "baboon logic," which I'd seen predictably employed at this site countless times.

I followed the baboons up the mountain to another large forested sleeping site which I call Giraffe Hill. We'd not seen any of the troops sleep at that location for some time, as it was quite out of the way. The baboons made haste in reaching the spot; I've never seen them move so fast along that route when moving downhill. The halted their march on the edge of Giraffe Hill, and proceeded to play, feed, groom: the usual restful activities. Everyone seemed to be wondering, What next?

The situation lost further clarity when I left troop 1 to investigate the whereabouts of Rainer, Tim, and their buddies. I found that troop in the forest down the mountain, still at their sleeping site. They did not sleep over the ridge, up on Giraffe Hill, or at any of the sites along that slope of the mountain. They were almost as far away as they could get, which I had previously guessed was out of audible range.

When I returned to troop 1 later in the day, I found they had resumed their usual behavior, following a known route to the feeding grounds. It took them longer than usual, but ultimately the situation was as it always ended: almost as if nothing odd occurred.

Many more lingering questions remain from this day than from your typical encounter scenario. Two in particular:

Why was the first troop's response so strong when the other troop was so far away?

That is, if they even heard another troop. If they did, then the movements make some sense. Troop 1 did not move in the right direction after the initial push - it was almost as if some other aspect of the troop mind took over the movements, and decided to make the most of the mess the young ones made.

I'm trying real hard to think about what could make the response so strong. For all we know, female vocalizations sound different when their issuers are at the peak of their reproductive fitness. Under such conditions, it would make sense for the males to pursue the other troop with greater vigor. A few words to the wise: the ethology community has nowhere near enough evidence to support such a hypothesis.
 
Even if this was a legitimate response to the presence of another group, why did dictate the choices of the troop mind for the entire morning? 

If the young males were really in control that whole time, then I've no idea how they managed it, because this is my only observation of such an event. As I mentioned above, its actually quite probable that the young males only influenced that first push, and afterward, the troop mind was just "going with the flow," so to speak. Still, what exactly would Aaron have to gain from continuing along this path?

The forest floor on Giraffe Hill is strewn with pine cones, so there's a great deal to eat. These baboons will sift through the needles for pine nuts, or if they're lucky, they will find unripe cones which have yet to eject their seeds. Baboons will lay into those cones, which is an impressive sight. I can rarely tear out a seed with my hands, but the baboons will crush and crunch through the rock-like shells of the cones as if it was a potato chip.

Since none of the troops have spent much time up on the hill lately, there ought to be a great deal more food laying around than in the usual, more traveled areas of the forest.

So why have I only seen the troop visit Giraffe Hill this one time in months, and why only under such bizarre circumstances?

Do the baboons need to be reminded of the presence of other feeding sites? When a large feeding ground is in season, and plentiful with food, do other options slip out of mind? This would say a great deal about the event/state driven nature of baboon cognition.

I like how I look through my logbook and try to find an interesting but brief (because I'm unexpectedly still very busy) story from the field, and it balloons into this massive endeavor which raises all these fascinating questions about primate behavior. I suppose there are worse things that could happen to a person.