I have now spent eight full days in the field following the monkeys, and the experience thus far has put me through a pretty wide array of emotions. Overall, its hard to say anything bad about this sort of work because the monkeys are remarkable creatures. Both titi and saki monkeys are pretty aptly described as adorable bundles of fur, so getting to spend most of your day with them is in many ways a treasure. But I’m also learning that it can be quite trying at times, and there are plenty of reasons why researchers out there are not dying to do intensive behavioral observations on these two species, despite their interesting and unique social organization and behavior.
A typical day of field work involves getting up around 5:30 in the morning right before it starts getting light out, picking up our breakfast and lunch (which we’ll eat in the field), and packing up the gear we’ll need for the day, ideally leaving camp by 6:30. There are three groups of titis and one saki group with individuals who are radio collared, so we’re able to use telemetry to locate the approximate location of the group and begin our behavioral observations as soon as we find them. Unfortunately the telemetry can sometimes be a bit of a headache, as the radio signal can bounce around and seemingly could be coming from any direction, and even when the telemetry is working well, spotting the monkeys isn’t always easy. The foliage in the rainforest is dense and the tops of tallest trees are often out of view, so you might even see some individuals climb to a particular tree but then they are out of view for over an hour. Meanwhile you’re stuck on the ground craning your neck to look above and see if you can catch a glimpse of movement, and inevitably as soon as you decide to take a break from looking, they sneak out of the tree and the next time you check the telemetry you realize your monkeys are elsewhere.
So what I really came to realize after the first few days in the field was how much of this sort of work is about patience. The long hours, the physical nature of tromping through the dense jungle, the unpleasantness of the insects and the rain and the humidity and everything else haven’t bothered me too much, but what’s been the biggest challenge is dealing with the amount of time one spends enduring those things when you can’t find or see the monkeys. I spent my first three days in the field with Amy being trained, but my first day out alone I started searching for the monkeys around 8 in the morning and saw no sign of them until 2:30 in the afternoon, when I finally found them in an area I didn’t even know was part of their territory. I was somewhat relieved to hear that such an experience isn’t unusual for a first-time field assistant, but it was horribly frustrating nonetheless.
Things have gotten much better already though, as I’m getting a better handle on how to use the telemetry and am getting more familiar each group’s territory and where they like to hang out. And as Amy has taught me, even the times when you’re unable to see any monkeys are opportunities to look around you and appreciate everything else the beautiful scenery of the rainforest has to offer. There are an absurd number of bird species here, strange and interesting varieties of plant-life, and when you’re just sitting there quietly off the trail and away from camp, there’s always the chance that something really cool like a tapir or an ocelot will come by. Being out in the thick of it so much has also given me the opportunity to see all ten species of monkeys that inhabit this area, (titi, saki, woolly, howler, spider, squirrel, capuchin, owl, tamarinds and most importantly pygmy marmosets, which are small enough to fit into your pocket).
And no matter how frustrated I might get at the monkeys when I can’t see them or figure out exactly where they are, when they do come into view those frustrations quickly subside as I am immediately drawn in by the fascinating and delightful nature of the titis and sakis. Yesterday after spending most of the morning waiting for a group of titis to come down from a spot high up in the canopy where I could not see them in the slightest, I got several hours worth of observation where at least one of the three individuals in the group was less than 20 feet away from me. At one point for a good 30 minutes I got a wonderful view of the adult male in the group Luciferus, and his offspring INF 10 (project code for an infant born in 2010, since they don’t get names until we can be sure of their sex) huddling together on a branch with their tales intertwined, taking shelter from the rain under some large leaves and every so often scrunching their furry little bodies closer together to stay warm. (the tail-twine is a behavior only seen in titi monkeys, and the fact that a father would be engaging in such protective social behavior is rather unique as well). About an hour later the infant was sitting in a thick tangle at about eye level not more than ten feet away, and we both stood there simply staring at each other for a good five minutes. I thought that after that experience I was developing a pretty good rapport with the INF 10, but then not long after he nearly peed on me so now I’m not so sure.
But what am I actually doing out there in the field besides following these guys around, having staring contests and nearly getting peed on? There a couple different components to the behavioral data, but the most basic task is simply recording the location of the individuals in the group every 20 minutes, either based on trail markers, previously marked feeding trees or GPS points. The meat of the behavioral observation work, however, comes from the focal samples. As frequently as possible, we conduct a 20 minute intensive observation of one individual in the group, recording each specific event that occurs in that time period, as well as logging the behavioral state they are in every two minutes, and the state of the other individuals in the group every four minutes. This amounts to a detailed record of all foraging, social, moving, resting, vocalizing and other sorts of behavior by the focal animal and the others in the group, as well as the relative proximity of the other individuals to the focal animal. While individuals and sometimes the whole group are frequently out of view, by the end of the day you have ideally collected enough data to give a fairly comprehensive account of what everyone in the group you were following was doing and where they were doing it. Thankfully we use a dictaphone for the focal samples so we can keep an eye on the monkeys (it is not uncommon to look down for a few seconds to record ranging data only to have your focal individual disappear from sight upon looking back up), but that also means when we return to the lab we have to transcribe all of our focal samples so we can upload everything into the database, all of which is a pretty lengthy process.
The protocols for the behavioral data collection are incredibly detailed and were a bit overwhelming at first (there are 55 possible social behavioral that can be recorded, for example), but I’ve realized how necessary such detail and precision is if you want to actually have quantitative data that allows you to say anything about primate behavior. Rather than simply reporting the subjective impression that male titi monkeys spend more time with their offspring, the project has data on the actual average distance between an adult male on its offspring, the frequency of which they are each other’s nearest neighbor, amount of time spent in contact, in proximity, and grooming, and so on. Another really important thing about the exactness of the data collection protocol is that data collected in the same way for titis monkeys, saki monkeys, and even the owl monkeys which are studied in Argentina, so the research done can as part of the monogamous primate project can be truly comparative.
And while the work I’m doing with Amy isn’t necessarily interested in all the details of something like the titis and sakis foraging behavior, for example, the fact that such data becomes part of the database regardless of the specific questions being investigated means that the project Eduardo and Tony (the PI’s) have set up has an incredible mass of data on pretty much all possible behavior that could be studied in tits and sakis. This data collection in Tiputini goes back all the way to 2003, so there is a ton of data in the database available for someone with the time and energy to analyze and perhaps develop new ideas for questions that might be asked about these primates’ behavior. So while the amount of time and energy it takes to go out into field day after day and day and intensively record everything that these animals do is substantial, the quality and quantity of the data available through such efforts is impressive and opens up the possibility for a lot to be said about the behavior and social organization of the monkeys being studied.