Monthly Archives: December 2018

Chimp Culture

Ask a cultural anthropologist if chimpanzees have culture and your answer will likely be “heck no – humans are the only species with culture”. However, ask a physical anthropologist and your answer might be a bit different. Physical anthropologists (also known as primatologists) often define culture as behaviors that are unique to a community of organisms (like chimps). Many of these behaviors can be observed being taught from adults to infants or juvenile.

Chimpanzee communities are known to exhibit community-specific behaviors. Some communities even exhibit dietary differences despite having access to similar food sources. Whether or not this is culture is up for debate.

I have been privileged to spend almost half of each month following the chimps here at Issa. I’ve witnessed two “cultural” behaviors. I’ve also observed many of the fascinating behaviors discovered by Jane Goodall in the 1960s that changed how we view humankind and one of our closest living relatives (don’t forget about bonobos being just as closely related to humans as chimpanzees).

I saw my first “cultural behavior” during one of my first chimp shifts. It is known here as a “grooming hand clasp.” Chimp communities often have specific methods of grooming that are unique to their community. The grooming hand clasp is performed when two chimpanzees each raise an arm to the sky and clasp each other’s hands, while one individual grooms the other. It is a very endearing behavior.

The second cultural behavior I have observed is “termite fishing.” It is unknown why some chimp communities will termite fish while others do not, even if termite mounds can be found in their home range. However, termite fishing is one of the behaviors that forever altered the way we view animals. Chimpanzees were the first species other than humankind observed to use tools! They fish for termites by stripping a long, pliable piece of bark from a sapling or branch and sticking it into a termite mound. Termites grab onto the “threat” with their mandibles (pinchers) and are pulled out of their mound and promptly consumed. Termite fishing starts at the beginning of the rainy season – which is also when termites begin their reproduction cycle of the year – and ends a couple months later.

Along with these cultural behaviors, the chimps at Issa exhibit many other behaviors and characteristics that make them so unique.

Some are quite intimidating to witness. Which is the point… Chimp “culture” is very male dominated. And to show their dominance, males will perform showy displays of strength. This can involve throwing their strength upon small trees to bend and snap branches, or even carrying and throwing branches at other chimps. Usually accompanied by loud screams from any chimps in the vicinity, the whole scene can be a bit unnerving if you’re close by. Especially unnerving is when male chimps saunter toward human observers and sit just a few meters away staring at us (we have one chimp in particular that will do this). Eye contact is often taken as a threat, so we avert our eyes and try to look extra small when this happens. Occasionally a male chimp will even run toward people (sometimes with their backs turned), slapping the ground or tree trunks as he goes along before swerving off in a new direction.

Chimpanzees, like most species, fear people. For us to study chimp behavior they have to be slowly habituated to the presence of humans. Lucky for me, the chimps at Issa (after several slow years) are reaching the end of their habituation process and beginning to ignore humans for the most part. The exception is the male chimps that occasionally test the nerves of the human observers.

The newly habituated chimps allow us to observe some of the subtleties of chimp behavior. Things like large adult males gently playing with a tottering infant. Or a mother tapping her back as she walks past her infant to tell her child to hop on.

Chimpanzees also display the artful skill of making nests. Yes, one of our closest relatives makes nests, like a bird. They bend a multitude of leafy branches high up in the trees to make a new nest each night. Sometimes they even make “day nests” when they have an extra lazy day and want to be more comfortable. I’ve even seen a subadult male chimp display his creativity while he was lounging on a rock. He looked at his surroundings, grabbed a nearby sapling, pulled it down so its leaves covered his rock, and promptly laid back down.

Although the chimpanzees here are habituated, it is still quite easy to lose track of them when they travel quickly along the mountainsides filled with lianas and thickets. When we lose them, we rely on vocalizations to find them again. It is rare that a full day goes by without a chimpanzee group starting a chorus of pant hoots and screams. Sometimes they vocalize seemingly to just hear their own voices. Sometimes it’s to exchange vocalizations with other groups within their community across valleys. And sometimes they vocalize during or after a rain, while shaking branches or charging around on the ground. These are known as rain displays and you can almost feel the exhilaration and awe of the individuals during these experiences.

The larger the group, the more often they send their voices echoing throughout the valleys. We have approximately 26 individuals in the community here and they form smaller groups to forage and travel together. Although it is somewhat rare for all the individuals to travel together, it does happen occasionally. On one of these occasions, we lost the chimpanzees briefly as they ran up the side of a mountain while vocalizing. When we reached the group a few minutes later, they had a dead bushbuck (a hoofed deer-like animal) up in the trees. They had successfully hunted! A large male carried his prize through the treetops and then back on the ground. Various individuals, even a mom and her infant, clutched pieces of meat in nearby trees. Eventually almost the entire community gathered around the kill, sharing meat with every individual, from the biggest male to the smallest infants.

If you ask me, chimpanzees have culture. Maybe culture isn’t the right word… It’s impossible not to view other species through the lens of our anthropocentric worldview. But I feel something akin to culture during rain displays. I see it in the grooming hand clasp. And I find it in the leftover tools at termite mounds. And it is an extraordinary privilege to have fleeting glimpses into the world of one of our closest living relatives.

A Day in the Life: Lions and chimps and monkeys, oh my!

This is the story of the craziest day I’ve had so far in Tanzania.

It was my fifth consecutive day with K1, a group of more than thirty red-tail monkeys. After four, fourteen-hour days behind me already, I was struggling to keep up with the group from the beginning of the day.

The monkeys were already making things difficult that morning, traveling higher and higher up the slope of Mchungwa valley, entering thickets impassible by humans, and spreading out so much that it was impossible to see more than a few monkeys at a time. Just as Judi, my field assistant for the day, and I sat down next to a thicket, thinking the monkeys were finally going to settle down for a few minutes, chimps materialized just ten meters away. We hadn’t heard them coming. Nor did they make any sounds as they climbed a tree, watching us as they settled into comfortable sitting positions. There was a female, her infant, and a juvenile. A bit further down the slope, we saw even more chimps popping up into the trees. By this time, most of the monkeys had melted into the tangle of vines covering the upper portions of the mountainside. Although chimpanzees rarely consume red-tailed monkeys (in fact – we have yet to observe the chimps preying on red-tails at this study site), our monkeys do not take any chances.

Along with the arboreal chimps, we could hear a few individuals screaming and running through the underbrush below us. So, there we were – stuck between a group of chimps and the impassible thickets. There was nothing to do but wait until the chimpanzees had moved further away so we could slide down the slope and try to find our way back to the monkeys, wherever they had fled.

In the short period of time Judi and I were stuck, unable to travel, the monkeys covered a long distance. It took us another three hours to find them, travelling so far along the valley that the mountainsides gave way to a plateau. Jubilant at finding the monkeys again, we got back to data collection. For me, that meant recording and collecting plant samples of the food items the monkeys were consuming. As I stopped to collect a sample of a new woodland plant that a monkey had nibbled on, I lost the group momentarily.

When I returned to the group, I heard a chorus of chirping (the monkeys make very bird-like vocalizations) and scuffling in the underbrush. Stooping down to get a better look, I saw a group of at least eight monkeys surrounding an owl. A few monkeys simultaneously jumped on the owl, while others vocalized and watched while perched on low hanging lianas. Then a monkey darted out and pulled the owl by its wing along the forest floor. This all happened multiple times while I frantically tried to video record and narrate the frenzy of activity. The owl was pulled into a nearby dried up river bed and the monkeys hovered over it for a few more minutes, shaking lianas above the bird but producing fewer and fewer vocalizations. Finally, the monkeys bounced away, starting a game of chase on the ground. I couldn’t get down to the riverbed without navigating a circuitous route to avoid thorny vines. So, by the time I made it to the owl’s previous location, the bird had disappeared. Lucky for the bird, this meant it survived the mobbing and flew away. Unfortunately for me, the bird’s quick disappearance meant I couldn’t get a good enough picture to identify the owl species.

(Monkey-avian interactions are quite rare, so we are hoping to publish this anecdote as a “short communications” paper in a primatology journal. And after looking through some bird books back at camp, we think the owl is an African Wood Owl.)

The owl mobbing was unique and strange enough, but nothing compared to the rest of my day.

The monkeys had settled down a bit, so we took a seat on the forest floor. Judi had just broken out her Tupperware for a late lunch when the alarm calls began. The handful of monkeys that were wandering the forest floor shot up into the trees and the entire group started traveling quickly downriver – all the time maintaining the highest intensity alarm calls I’ve ever heard from them (their alarm calls – like their other vocalizations – are also very bird-like). The constant chirping drowns out all other sound as I rushed after them, stumbling through the rocks of the dry river bed while trying to follow the movements and sounds above me.

Then they stopped.

I looked around me, expecting to see a predator of some kind. Maybe African Wild Dogs, maybe a Jaguar. Or maybe just a bumbling bush pig that the monkeys mistook for a threat. But the intensity of the alarm calls coming from high in the trees put me on edge.

Then I saw one, then two, female lions cross the river bed a mere thirty meters ahead.

They didn’t look at me. They just plodded across the stones and disappeared, almost before I could even register what just happened. Lions hadn’t been seen in this area since 2014. Also…. those were FEMALE lions! The hunters! Even though the lions didn’t look at me, they had to have known I was there – either by smell or the noises I made stumbling through the rocks. What if there were more? The growth on either side of the river made it impossible to see what could be hiding in the foliage. I quickly used my radio to call Judi (who in the midst of her lunch hadn’t been able to pack everything and keep up) and told her what I saw and that she should probably stay put. I would make my way back to her. My heart pounded and my legs were weak as I staggered back to her. We met each other wide eyed and suck in more air than normal as we discuss our game plan. As we crept along the river bed, towards the monkeys but also possibly towards lions, we exchange nervous looks. It’s not like we were provided with lion defense training. As we made our way outside the forest and discovered no hidden lions, we laugh in relief.

“Almost any organism around lions might be a potential prey item, and for people to think that they are an exception is folly” says Luke Dollar, director of National Geographic Society’s Big Cats Initiative. “I would imagine that every other primate that co-exists with big cats is acutely aware of the position they hold relative to the top predators of the world.” Read more here.

Lions or no lions, we still had to catch back up to the monkeys.

And they were making their way down a strip of forest sidling Moporomoko Kubwa – translation: “big waterfall” (also dried up until more rains fall). Which meant we had to climb down the steepest trail in the study site – a trail that I’ve fallen down more times than not. With adrenaline still pumping, we cautiously made our way down the trail – only to find that the monkeys were nowhere in sight. Two hours spent searching the forests, up and down slopes – once again made difficult by the tangles of vines and thorny vines – yielded no monkeys. Which meant a climb back up the Moporomoko Kubwa trail in case we misread their traveling intentions. Then halfway up the trail, a downpour began. We were soaked before we could make it to the top to don our raingear. Chimp vocalizations began echoing through the surrounding woodlands and forests and we knew the chance of finding the monkeys had dropped to zero.

Red-tailed monkeys don’t like the rain and they don’t like chimps.

Although our days don’t normally end until 7:00pm, at 4:00, on this last follow day with this group, we didn’t feel bad about heading back to camp a bit early. After a 45-minute hike in a downpour, we crashed at camp. We tell our story. Everyone is shocked. Some are a bit nervous. And almost all the foreigners are jealous about our experience and excited about the possibility of having lions back in the area.

My fingers were so numb from the cold rain that it took about 30 minutes of clutching a mug of hot tea before I could text my supervisor the news of the day. With too many details to fit in one text, I basically just bullet point the day. The next day I typed everything out – as scientifically as possible.

A month and a half later, I’m finally typing out the narrative form. Lion encounters and the owl event are rare occurrences here (although there were several lion sightings over the course of the next week – I even saw some lion prints and scat a week later). But the rain, chimps, and treacherous hiking are very typical indeed.


I hope this paints a picture of how unexpected life in the field can be.