Monthly Archives: March 2012

Focal Individual Follows

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My field assistant and I following our focal target

Its 8:05 am and Ferdinand is crashing through the forest shaking branches, pounding on tree trunks and making a big display of his dominance to approaching group members. Meanwhile, in a nearby area, Titan is up in a tree feeding, Gremlin is playing with her infant below, and Freud and Faustino are grooming one another in the tall grass. With all of this going on, how do you get the data you need to answer a research question? In these situations, a person’s natural reaction is to focus on the most exciting event: Ferdinand’s display. It is loud, eye-catching, and, at times, outright alarming (particularly if he’s coming your way!).  That is why, if you approach observational research in an unsystematic manner, your data will be biased towards these exciting events and will overlook more subtle behaviors, like the quiet grooming of Freud and Faustino. It would kind of be like studying a group of students but only taking data on the class clown or bully. Obviously, these data would not represent the behavior of the class as a whole. This is why many scientists studying animal behavior conduct something called “focal individual follows”. Continue reading →

Where have all the chimps gone?

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Leaves from the mpapa tree (with no fruit)

The chimpanzees of Gombe have gone missing, at least most of them. The majority of community members have not been seen in about two weeks. They have done what chimps do when their primary food sources (fruit) come to an end….scatter. When I first got to the park the chimps were primarily eating mpapa (local name), small fruits that grow on trees with compound leaves that look like hands, with five leaflets growing out of a single point. It makes identifying these trees very easy. It also made finding the chimps relatively easy as there were several groves where the chimps could often be found. When they were not feeding on these dark little fruits the were eating bulinda mkwavu, little reddish-pink fruits that grow on shrubs and can be found in large patches in the higher altitudes of the park. However, in the past few weeks both of these fruits have come to an end, leaving mostly leaves and only a few scattered vine fruits for the chimps to eat. I have spent the past three days searching for chimps and have not seen or heard a single one. I have been to some of the highest points in the park, gone to both the northern and southern borders of the Kasekela community and, it seems, nearly everywhere in between. It is true that there have been surprisingly regular sightings of Frodo and the G-family females, which reassure us that there are still chimps in the park, but you can only follow Frodo so many times… Continue reading →

Rough-grunts

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Sampson grooming Frodo a few minutes after the food-call bout

On Friday my focal chimp was Frodo, the ex-alpha male of the Kasekela community. My field assistant and I had been following him for the past few hours after finally discovering him in the southern portion of the park. He was alone and traveling in frequent bursts through a dense patch of machaca (terrible vine tangles). Pausing periodically to feed on a few leaves or ants, he eventually emerged from the vines.  At last able to walk on two legs again, I found myself bypassing my field assistant, who is typically in the lead. Frodo hadn’t been feeding on anything substantial for the past few hours and I could feel that he would soon arrive at a more impressive food patch, the type of event my research focuses on. After a few minutes of walking along the trail, Frodo paused and looked behind him. There sat Freud, Frodo’s older brother. Continue reading →