After we arrived, I took a little tour of Gelada camp: a scattering of tents at the head of a long, wide valley. There is a kitchen tent, a storage tent (tattered and torn from the relentless wind and sun; Tyler had bought a replacement for it in Addis), a little shower tent, a handful of tents for the researchers and staff, and a rough little latrine, screened off on the side towards camp, but open towards amazing views in other directions.
The bare heathland seemed more like Scotland than Africa, as if we had driven so high that we had somehow found a shortcut in the sky to Europe. But the dizzying view of the rift valley below made clear we were somewhere else entirely.
We piled our more vulnerable belongings inside the kitchen and storage tents to protect them from the rain.
Gathering outside the kitchen tent.
Before long Peter returned from the field, where he had been collecting plants for nutritional analysis, and welcomed us to Guassa. We huddled in the kitchen tent and drank tea and ate peanut butter and honey sandwiches waiting for the rain to stop before setting up our own tent.
In the kitchen tent, I tried reading the labels in Amharic on the honey jars and tea bags. I could work out that honey was mar, water was wuha, and tea was shai, but couldn’t make out much else. Bedulu saw what I was doing and helped out, pronouncing the words for me. He asked in Amharic if I would be visiting the farms while here; unfortunately there wouldn’t be time for that.
Guassa camp.
Wanting to get the tent set up before nightfall, we eventually settled for a lull in the rain, rather than waiting for it to stop completely. We chose a spot that had been previously occupied, still marked by a bare patch on the ground. Fitting together poles and stakes with hands numb from cold and wet with rain brought back memories of camping trips in Minnesota’s Boundary Waters.
Once the tent was set up, I changed out of my rain-soaked town clothes and put on layers of field clothes. Even after the rain stopped, and even inside the kitchen tent, I kept my raincoat and hat on for warmth.
The other researchers gathered in by sundown, and we ate dinner: huge bowls of rice with a sauce of tomatoes and onions. Dinner started with placing big pots of rice and sauce in the center of the table, surrounded by bowls for the nine people in camp: Peter, the project co-director; Ethiopian staff Bedulu and Shoa; the outgoing volunteer, Taylor; the incoming volunteers, Carrie and Bryce; visiting researcher, Morgan; and Tyler and me.
Then one person served rice and sauce until each bowl was piled high with what seemed like enough food for three people in each bowl. Then the salt, chili sauce and berberi (the local spice, a dark orange in color) were passed around for flavor, and everyone ate and ate, not saying a word, just shoveling in the food. Everyone emptied their bowl, hungry from a long day’s work. Then we talked, telling stories about the monkeys and people of Guassa and other places we’d been, and drank tea. I drank several cups, trying to warm up, holding the mug close between sips to warm my body.
Conversation included the researchers’ names for local places and things. Where did the geladas sleep? Darjeeling, down by the Cliffs of Insanity. Some others might be sleeping in Norway. During some parts of the year, the monkeys eat Injury Berries, which despite their name are supposed to be not only harmless but very tasty.
By 8:00 I was nodding off, and soon we all went off to our separate tents. I snaked into my sleeping bag wearing heavy winter socks, field pants, t-shirt, and long-sleeved field shirt, with the collar turned up to warm my ears. Even with a wool blanket on top of my sleeping bag, I shivered with cold.
I slept in fits and starts. The tent shook in the wind, then beat like a drum when the rain fell. Having drunk all that tea before bedtime meant I had to get up repeatedly in the night, slip on my rain-soaked shoes, unzip the tent, and step outside for a bit in the howling wind and rain.
Yesterday we drove up from Addis Ababa to Guassa – up and up and up. Up out of the crowded streets and diesel fumes of the city into the open country, up winding roads. The main road has been paved now and traffic moved quickly.
Packing up the car
We started at 7:00, packing our luggage and all the supplies Tyler had bought in town: a storage tent with long metal poles (tied to the roof of the car), two mattresses, bags of food for us and the other people in camp. Tyler let me ride shotgun so I could enjoy the views that he knew well from previous visits; he sat in the rear passenger seat snugly surrounded by mattresses and supplies.
Then we drove to the transport operator’s house to pay him for this trip, my return on Saturday, and Tyler’s return in six weeks. We were supposed to bring up cylinders of propane gas as well, but the driver was worried that would make the load too heavy for the car to make it up the steep road into camp, especially now that the rains have started.
Some things that make Ethiopia seem really different from other parts of Africa:
Horse carts on the road to Guassa
Horses. I don’t remember seeing anyone riding horses in East Africa. I’ve heard of horseback safaris in Kenya, but local people don’t have horses. But here we saw lots of horses: people riding thin little horses, the horses decorated with bright red tassels. Thin little horses pulling little carts with three or more people sitting across. I don’t know why more people don’t use horses in Africa – they seem much more economical than cars for subsistence farmers. Maybe disease is more of a problem for horses at lower elevations? Or they just never caught on?
Donkeys are good for carrying heavy loads on mountain roads
Donkeys. Lots of donkeys, with huge loads strapped to their backs, wandering aimlessly about or being driven here or there. Many of them carried huge stacks of flattened, dried cow patties: fuel for the home fires. Loads that in East Africa would be piled up on a bicycle are carried by donkey here. Again, seems much more efficient to use pack animals. Some of the donkeys were very shaggy, which is very sensible given the cold here.
Hay bales and cattle.
Cows. Most of the cows look similar to East African cows: long horns, big shoulder humps, usually reddish brown in color. But we passed a herd that looked like Wisconsin dairy cattle: white and black cows grazing in an open field.
On the road we sometimes passed the whole family herd on the move: horses, sheep, goats, and cattle all traveling together with the men, women and children herding them along, hitting them with sticks to get them to move away from oncoming cars.
The higher we climbed, the more fabric people wore wrapped around themselves: white cotton drapes with colorful trim at one end, worn wrapped around the shoulders, and sometimes wound around the head as a turban. Higher up people wore wool blankets over their shoulders. Starting to think I should have packed more winter gear…
The paved road, like many others in Africa, was built by the Chinese. I suppose much (if not most) of international aid is rather selfishly motivated. Much of American and European international aid seems directed to projects that make donors feel better about themselves, or to promote things they happen to care about, such as conserving wildlife. I suppose Chinese aid is just as selfishly motivated as Western aid, but roads at least seem a particularly useful, practical sort of aid. Road improvements make life easier in all sorts of ways for people. Though of course faster roads lead to more deaths, not just of people, but of gelada monkeys, Ethiopian wolves, and other wildlife.
Along the way, we passed cars and trucks in various stages of break-down and disaster. One truck with two trailers hung from a bridge, having plunged off the side of the road.
Goodbye paved road! This is where the car broke down.
About halfway to Guassa, in terms of distance, we left the main road and took an unpaved little branch road that climbed steeply up into the hills. The car soon broke down. While the driver tinkered with the engine, Tyler showed me the plants growing alongside the road: lots of thyme, mint, dandelions, and various yellow, purple and red flowers, including red-hot pokers. Thyme grows all over Guassa.
Plant with spikes right on the leaves.
“That’s the scariest plant I’ve ever seen,” Tyler said, pointing to a plant that had inch-long thorns growing right from its leaves.
We shared a Snickers bar (our first food of the day, since the hotel doesn’t serve breakfast until 8:00) and some water. The road had already climbed so far above the paved road winding below that trucks looked like toys.
The driver got the engine going again, and we climbed into the car, driving higher and higher. We passed through forests of Eucalyptus trees, plantations clinging to steep hillsides.
Terraced fields and a glimpse into the valley beyond.
We climbed up high enough to see down into the Rift Valley, and what had seemed like amazing views before now seemed barely worthy of notice. Even with the dust and late dry season haze in the air, the valley floor seemed impossibly far away. Valley doesn’t even seem the right word for it — a valley is gentle and pleasant. This is more like a canyon, a chasm, a rent in the crust of the earth. This is what the view from Gombe would look like if someone pulled the plug on Lake Tanganyika.
Despite the views, lulled by a gentle rain and the long drive and jet lag, I dozed off.
First sighting of geladas
Sometime later, I woke up, hearing Tyler calling out that there were geladas ahead. We stopped and looked out the window to see a small herd of monkeys foraging in the grass near a cell phone tower. I took pictures, excited to see geladas for the first time. Tyler kept his amusement to himself, knowing that these views of distant, shy monkeys were nothing compared to what we would see of the research monkeys.
Finally, after hours of driving through landscape dominated by human activities — farms, fields, houses, tree plantations — we reached the Guassa: a vast, open country of hills covered by grass, flowers, herbs, and strange Afro-montane plants like giant lobelias.
Guassa is the local word for the kind of grass used for thatching roofs. For the past 400 years, the local people have protected this land in order to ensure a supply of thatching. In doing so, they also conserved a rare patch of natural habitat, and some of the creatures that only live here, in the Abyssinian Highlands: gelada monkeys, Ethiopian wolves, and many other endemic species.
We passed the Wolf Lodge, where the few tourists that make it up this way stay, and where the Frankfurt Zoological Society supports the study and conservation of the Ethiopian wolves. A herd of gelada monkeys scrambled up the cliff near the lodge. Tyler thought the researchers must be nearby but we didn’t see them. We continued on towards camp.
The road wound on and on, up into the hills. Tyler called for the driver to stop, then got out and scouted around until he found the faint track that led away from the main road towards camp. We drove up this steep, rocky track, until we could see camp emerging, a scattering of tents nestled at the head of a broad valley. This was where Peter Fashing and Nga Nguyen have been studying gelada monkeys since 2005. Tyler spent 13 months working as a volunteer on their study before starting graduate school at Minnesota, and now he was back to start his PhD research.
The two men in camp, Shoa and Bedulu, welcomed us. They greeted Tyler especially warmly, clearly very happy to see him again. Speaking Amharic, they told Tyler that the others were still out in the field. They helped unload the car. We thanked the driver, confirmed that someone would be back to pick me up on Saturday, then watched him drive away. An augur buzzard hovered over the edge of the cliff above camp, perfectly still, like a kite, holding steady in the strong wind blowing up from the valley far below. The air smelled of thyme, and rain.
I’m sitting outside the Taitu Hotel in Addis Ababa, capital of Ethiopia. According to the paper I read over coffee this morning, Ethiopia is the second most populous country in Africa (with some 82 million people), and has the fifth fastest growing economy in the world. Addis is on a high plateau some 7700 feet up, and it’s chilly here.
View from my balcony at the Taitu Hotel
The hotel is the oldest in Ethiopia, and is named after the Empress Taitu, who led a force of cannoneers against Italian invaders in the Battle of Adwa in 1896.
Ethiopia is unlike anywhere else I’ve been in Africa. In the 19th Century, when the European scramble for Africa subjected most of this vast continent to colonial rule, Ethiopia dealt the Italian invaders a humiliating defeat and maintained its independence. The Italians invaded again under Mussolini, and occupied Ethiopia for five years (1936-1941) before getting kicked out by the British, who restored Emperor Halie Selassie to the throne. Though Selassie was considered the second coming of the Messiah by Rastafarians, he was deposed by the Derg, who took over in 1974 and ruled Ethiopia as a People’s Republic until the end of the Cold War.
At the airport yesterday, we didn’t find the car the hotel had sent for us, so Tyler haggled with taxi drivers in Amharic. Our luggage didn’t all fit in the small car, so the driver tied my suitcases to the luggage rack on top of his car. Driving through the city felt much like driving through other African capitals in some ways, though very different in other ways. With about 3 million people, Addis is similar in size to Nairobi and Dar es Salaam. Like those cities, the winding roads are crowded with taxis, minivans, and people. The streets are lined with small shops with brightly colored signs. But here most signs are written in Amharic, which uses its own alphabet, based on the writing system for Ge’ez, the liturgical language of the Ethiopian Orthodox Church. Ge’ez has a longer history as a written language than English, with some early inscriptions dating back to the 5th century BC.
My table at the Taitu Hotel, illustrating the Amharic script, Christian heritage, and contemporary beverage preferences..
The Ge’ez script has roots in common with Hebrew and Arabic, but doesn’t look very much like either, and all the signs in these odd, lovely letters make clear that we’re in a different world now. I’ve been trying to learn the script, and spent time on the plane copying out whatever phrases I could find. Each letter represents a syllable rather than a consonant or vowel. With 33 consonants and 7 vowels, there are 231 different letters to learn, but they vary in a sort of systematic way. Syllables that start with “m,” for example, all have a pair of circles connected by a horizontal line, like a set of spectacles. If the spectacles are unadorned, the syllable is “mä.” If the spectacles have a handle on the right, like a lorgnette, then it’s the syllable “ma.”
At the airport, on the city streets, many different sorts of people mill about. Some people have jet-black skin, and look like they could be from southern Sudan or Uganda, while most others have lighter brown skin and narrow noses. Ethiopia is a diverse country, with many different languages and peoples, and stands at a crossroads between Africa and Arabia. At the hotel, some of the visitors are dressed in long white gowns and Arab headdresses.
After checking in, Tyler and I walked through the city for a while to get our bearings. Our hotel is in the Palazzo neighborhood, with many old buildings dating to the Italian occupation. Before we had gone fifty feet from the hotel, a young man called to me – “Hey, are you looking for something? I can sell you my sister.” At a street intersection not much further along, small children reached up to touch my hand, begging for money. A pair of vultures circled high overhead, and a pile of garbage smoldered on the street. The city air was hazy and acrid, smelling of diesel fumes and burning garbage. Further down, shiny new office buildings stood on wide, smoothly paved streets. Buildings under construction arose in a framework of scaffolding made of roughly lashed together saplings. At the intersection of two major streets stood a huge bore cannon that was fired once, cracking the barrel.
There are a few tourists here, and I saw one white United Nations car, but the place generally feels off the beaten track. We drank excellent coffee in a small café, and ate delicious local food for lunch and dinner at the hotel: spongy injera flatbread with different sauces, vegan for lunch and meaty for dinner. After dinner went to the hotel’s jazz club to see a local band playing straight-ahead American jazz-funk – songs including Stolen Moments, Footprints, and Freedom Jazz Dance. What a country!
According to the GPS map on the little screen on the seat in front of me, we’re flying over the North Atlantic now, midway between the spot where the Titanic went down in 1912, and the Corner Seamounts.
Usually when I fly to Africa, the first leg is a flight to Europe, usually overnight. Then, after an early morning layover in London, Brussels or Amsterdam, we board a southbound plane that flies all day to Nairobi, Entebbe, or Dar es Salaam. But today we’re flying on a Boeing 787, which can fly straight to Africa on a single tank of fuel. And instead of taking off in the afternoon or evening and flying overnight, we left Washington Dulles in the morning. After some 13 hours in the plane, we’ll arrive in Addis Ababa Sunday morning.
While much of the routine is familiar, there have been many changes over the past 20 years. When I first flew to Africa, they showed movies on a few small, dim screens in the forward section of the cabin. Now the back of every seat has its own screen with a choice of movies, television, and GPS maps.
It’s fun to watch the plane slowly crawl across the world on the GPS map. Twenty years ago, GPS technology was just becoming available for civilian use. Towards the end of my time in Kenya, Jeanne Altmann brought a GPS unit to Mpala to help map the baboon ranging patterns. It was an expensive, bulky, heavy box, and in those days the US government scrambled the signal so that all locations would be off by an unknown number of meters. But it pinpointed locations in a magical way. At the time, I had been drawing range maps onto photocopies of a map of the study area, estimating location with reference to map features like the meandering wall of the cliff, which snaked along in parallel to the Ewaso Ng’iro river, and the streams, roads, and bomas (corrals for cattle and sheep). When we got up into the plateau above the escarpment, landmarks disappeared, and my estimations of where we had gone got worse and worse. A GPS would have been nice to have!
All these new gadgets, like GPS wristwatches and handheld units with global terrain maps, make it seem like the field of primatology has moved quite slowly in comparison. We still do basically the same thing: following primates around, watching what they do, recording behavior as systematically as we can, trying to answer research questions that really haven’t changed all that much from the 1970s: Why do animals live in the sorts of social groups that they do? What explains differences in behavior between males and females? How does that relate to their ecology?
The questions are simple to state but hard to answer. Ecology, evolution and behavior are all complicated, with lots of moving parts, and it can take many years to get enough data on enough individuals to answer key questions. But even the field does move rather slowly, new tools like GPS technology have helped greatly. We can track locations precisely now. And just like in real estate, the three most important things in much of behavioral ecology are location, location, and location. Animals need food, safety, water, and mates, and the availability of all these key resources vary in space and time.
At Mpala, each day the baboons traveled a circuit, leaving the safety of the sleeping cliffs in the morning to search for food and returning to safety for the night. One of my favorite parts of studying baboons in Kenya was arriving at the top of the sleeping cliffs before dawn to watch the sun rise over Mount Kenya. The baboons seemed to enjoy the view too, basking in the sun’s rays to warm up from the cool night before starting their day’s search for food. But where to go? How do they decide? How does a group of 50 or 60 quarrelsome monkeys pick a path for the day?
Following baboons at Mpala research camp, Kenya, in 1993
Answering questions like these requires lots of good location data. And now they’ve got GPS units small enough to go on radio collars, enabling researchers to watch the daily paths of baboons and other animals, just as I’m watching the plane on the screen on the seat in front of me creep closer and closer to Africa.
Today I’m on the plane from Minneapolis to Washington, DC, the first leg of my journey to Africa, where I’ll be visiting Ethiopia and Tanzania.
Twenty years ago, I traveled to Africa for the first time, a few months after graduating from college. Everything was new to me then: the shots and pills for yellow fever, typhoid, malaria, and other tropical diseases; packing long sausage duffel bags with everything I thought I might need for a year of living in a tent; the long flights in which the trans-Atlantic flight to Europe was just a step along the way; trying to learn the basics of Swahili, a language that has somehow gained a reputation for being easy despite having half a dozen different noun classes and totally different grammar and vocabulary from European languages.
Back in 1992, I studied olive baboons at the Mpala Research Camp in the highlands northwest of Mount Kenya. Since then, I’ve spent about a third of my life in Africa. After ten months studying baboons in Kenya, I’ve spent years studying chimpanzees in Uganda and Tanzania. This summer, I’m returning to Gombe National Park in Tanzania, but first I’m traveling to a place that’s new to me: Guassa, in Ethiopia.
My graduate students are working at each of these sites. At Gombe, Lisa is studying food-associated calls of chimpanzees, and Andrea is studying sexual coercion among olive baboons at Gombe. I’ll be traveling to Guassa with Tyler, who will be studying intergroup aggression in gelada monkeys.
Packing for Africa this time involves packing for two totally different climates.
Gombe and Guassa both lie on the Great Rift Valley, a vast set of connected trenches that stretches 3,700 miles from Mozambique to Syria. That’s about as far as going from La Paz, at the southern tip of Baja California, all the way to Fairbanks, Alaska.
This steep, narrow, deep, long valley results from the forces of plate tectonics tearing Africa apart. Eventually, the Horn of Africa will become a big island off the coast of the rest of Africa, just as Madagascar peeled off from Africa some 135 million years ago.
Parts of this valley are underwater: the Dead Sea in Israel, the Red Sea, and the African Great Lakes.
Gombe stands on the edge of a flooded portion of the Great Rift Valley: Lake Tanganyika, the longest and second deepest lake in the world. The Great Lakes of North America pale in comparison to the African Great Lakes. Right now I’m flying over Lake Michigan, which is an impressive body of water, and it parts is over 900 feet deep. Lake Tanganyika, however, is nearly a mile deep, second only to Lake Baikal in Siberia (another rift valley lake).
People often ask me if it’s hot in Africa. What’s hard to grasp is just how huge and varied Africa is. Sure, some parts of it are hot – just like some parts of North America are hot. Getting off the plane in Dar es Salaam, on the east coast of Tanzania, the heat and humidity hit you like a wall.
But Africa is big enough to hold all of the United States, China, India, Japan, and much of Europe. It stretches from a bit further north than Nashville to as far south as Buenos Aires. And much of equatorial Africa lies on high plateaus, which are much cooler than the coastal lowlands.
At the lakeshore, Gombe is 780 m above sea level (about half a mile), and rises steeply up the rift escarpment to peaks up to 1,623 m (over a mile high). The temperature is pleasant year-round. Guassa, on the other hand, is over 3,000 m – over two miles high. From what I hear, it’s cold up there!
I know what I need to pack for Gombe: t-shirts, army surplus fatigues, Kosovo soccer cleats (the best shoes for keeping a person from sliding down the steep hills), and a waistpack for fieldwork, and swimsuit, fins, snorkel and mask for swimming in the lake.
But I’m less sure of what to pack for Guassa. The list of suggested field clothes includes a short-sleeved t-shirt, a long-sleeved t-shirt, a fleece jacket, a wind-proof jacket, raingear, long pants, long underwear, wool hat, a broad-rimmed white hat to go over that (apparently the gelada monkeys know that researchers wear white hats and are therefore safe to approach), and waterproof gumboots.
In the end I packed two suitcases: a big one for Guassa, and a smaller one for Gombe. I hope I’ve got what I need!
As George Carlin says, “It’s inevitable when you buy the pet. You’re supposed to know it in the pet shop. It’s going to end badly. You’re purchasing a small tragedy.”
The same goes for studying animal behavior. Anyone who spends enough time in the field, getting to know the lives of animals, will also witness their deaths. In a new paper, “Pathologic lesions in chimpanzees (Pan troglodytes schweinfurthii) from Gombe National Park, Tanzania, 2004-2010,” we report on some of the things we’ve learned from chimpanzees who have died. This paper, led by Karen Terio at the University of Illinois, involved a large team of field researchers, veterinarians, and pathologists.
I started studying chimpanzees because I was interested in how they lived. But in studying their lives, I’ve seen many of their lives come to an end. In this way, studying chimpanzees is a bit like being an Elf in J. R. R. Tolkien’s Middle Earth. In Tolkien’s world, the Elves live for centuries, dying only if they encounter some mishap, such as being slain in battle. In a single life, an Elf such as Elrond watches sadly as generations of mortal men come and go. In a similar manner the generations of chimpanzees, though long by the standards of typical mammals, pass more quickly than those of our own species. Jane Goodall, who has been watching chimpanzees at Gombe since 1960, has seen entire generations come and go. Chimpanzees that Jane saw as newborn babies have grown old and died, and their children, grandchildren, and now great-grandchildren have been born. I’ve only been working at Gombe since 2001, but this is still long enough that many of the chimpanzees I’ve gotten to know there have since passed on: Fifi, Goblin, Vincent, Ebony, Andromeda, Patti, Ebony, Sherehe, Shangaa, Echo, Yolanda, Malaika, Kris, and others.
I knew each of the 11 chimpanzees we describe in this new paper, except for a stillborn baby. I was involved in various ways with documenting the ends of their lives, such as taking observations during their final days, helping with the recovery of their bodies after death, examining the bodies immediately after death, organizing and participating in the necropsies, burying the bodies and recovering their skeletons from their graves, after they had been buried for at least a year. My student Claire Kirchhoff examined these skeletons for evidence of trauma.
Determining the cause of death is important for many reasons, including understanding chimpanzee life histories and identifying threats to their conservation. Because my research focuses on aggression, it’s especially important for me to know the cause of death. Did they die from aggression, or some other cause? In each case, it’s important to document carefully the relevant evidence.
Graucho Marx said, “Outside of a dog, a book is man’s best friend. Inside of a dog, it’s too dark to read.”
I’ve never tried reading inside a dog, but I’ve ended up sending more time looking at the insides of chimpanzees than I ever expected. If I had known what the future held for me, I would have taken some proper anatomy courses. But fortunately at Gombe, we’ve benefited from a wide range of expertise, including the Health Monitoring Project led by Elizabeth Lonsdorf and Dominic Travis, and the virology study led by Beatrice Hahn. We’ve been able to store chimpanzee bodies in large freezers until we can assemble teams of experts to conduct necropsies. We send tissue samples to pathologists and molecular virologists to gain a finer grained understanding of the causes of death.
I study violence in chimpanzees, not because I like violence (I don’t), but because it plays such an important role in the lives of chimpanzees – and as one of the two species most closely related to humans, chimpanzee violence can help us understand violence in our own species. Chimpanzee violence caused 36% of deaths in this study – more than any other factor. Andromeda and Patti were killed during intergroup attacks. Vincent was killed by members of his own community. Ebony – found dead with a broken neck and puncture wounds – almost certainly killed by chimpanzees, and likely one or more of the males of his own community.
One of the humbling things about research is that often, even with all the expertise we can muster, there is much that we will never know for sure. One such case involves the adult female Echo, who became a long-term resident at Kasekela at about the same time that I did. I caught my first glimpse of Echo during one of my first days in the field as Director of Field Research at Gombe, back in January 2004. While we were watching a large group of chimpanzees feeding in the trees above a steep valley, videographer Bill Wallauer pointed out a new immigrant female chimpanzee with a pretty face and an asymmetric, bumpy sexual swelling. Bill recognized her from pictures he had taken in 1999, and thought she might be a female seen during an intergroup encounter in 2003. We named her Echo because she seemed to keep bouncing back. Unusually, Echo had immigrated together with her juvenile daughter, who we named Eowyn, after the heroic shieldmaiden from Tolkien’s Lord of the Rings.
Eowyn inflicting fatal trauma on the Witch-King of Angmar
Usually, females only move from one community to another as adolescents, before they have children. Infants of immigrants face a high risk of being killed by the resident males, as nursing infants fathered by other males represent both genetic competition and an unwelcome form of contraception. But Echo chose a good time to immigrate: her daughter Eowyn was weaned, and Echo had a full sexual swelling. The Kasekela males left Eowyn alone, and Echo quickly conceived a daughter, Emela.
Genetic analysis of fecal samples confirmed that Echo used to live in the Kalande community. Her departure from Kalande showed just how bad the decline of that community had gotten. Usually, once females have settled into a community and have started having babies, they stay there for life. But females seem to prefer living in a community with multiple males, which may be important both to protect them from intergroup aggression and to provide them with some good options for mates. Echo left when the number of adult males in Kalande dropped to one.
We also learned that Echo was infected with SIVcpz, the virus that is the immediate precursor of HIV-1, which causes AIDS in humans. Four of the 11 chimpanzees in the new study were infected with this virus. Until recently, it was widely assumed that SIVcpz was harmless in chimpanzees. We learned from studying Gombe chimpanzees, though, that infection with this disease greatly increases mortality risk. Two of the chimpanzees in this study died from AIDS-like symptoms.
Echo and Emela
I particularly remember Echo from a day in March 2006. In the late afternoon, the chimpanzees climbed high into a hill above Kasekela valley, into an open woodland. They climbed into the short, stunted trees to feed, rest and groom. Echo climbed rested on a low limb and groomed with Tubi, Bahati and her son Baroza. All seemed peaceful and happy. Echo had immigrated successfully, settled into Kasekela, had a daughter, and made friends.
But this was not to last.
Paralyzed "Patina"
In November 2006, which happened to be my last month of being based full time at Gombe, field assistants monitoring the Kalande community reported that one of their females, Patina, was sick. Together with vet Iddi Lipende, I traveled down to Kalande to investigate. We found a female chimpanzee lying in a dry streambed, her legs apparently paralyzed. She looked at us fearfully. She was too weak even to shoo away the flies that gathered at the wounds she had inflicted on herself, dragging her broken body along the stones of the dry streambed. She died within a few days.
In the following months, analysis of genetic samples found something puzzling: new fecal samples continued to come in from a female who was an exact genetic match for Patina. Apparently it wasn’t Patina who lay dying in that streambed – it was someone else. Given that the Kalande chimpanzees aren’t habituated, a case of mistaken identity was not so surprising. But the puzzle remained: who was the female who died?
Around this time, Echo’s daughter Eowyn showed up in Kasekela without her mother – something unusual for such a young chimpanzee. And genetic analysis of the tissue from the dead female found that she was, in fact, Echo. She had gone back to her home community of Kalande and died there. In her weakened state, she looked so different that none of us had recognized her. Her infant Emela had disappeared and must have died as well.
The necropsy found that Echo had a broken spine, but we don’t know how she broke it. She didn’t have the other injuries typical of a chimp attack – no canine puncture wounds, missing fingers or toes – so it seems unlikely that chimpanzees had killed her. Did she fall from a tree? If so, why? Was she chased by other chimps? Or did she just have bad luck? We will never know.
Here are the publications where we report some of the findings discussed here:
Keele, B. F., J. H. Jones, K. A. Terio, J. D. Estes, R. S. Rudicell, M. L. Wilson, Y. Li, G. H. Learn, T. M. Beasley, J. Schumacher-Stankey, E. E. Wroblewski, A. Mosser, J. Raphael, S. Kamenya, E. V. Lonsdorf, D. A. Travis, T. Mlengeya, M. J. Kinsel, J. G. Else, G. Silvestri, J. Goodall, P. M. Sharp, G. M. Shaw, A. Pusey, E. and B. H. Hahn (2009). “Increased mortality and AIDS-like immunopathology in wild chimpanzees infected with SIVcpz.” Nature460: 515-519.
Rudicell, R. S., J. H. Jones, E. E. Wroblewski, L. G. H., Y. Li, J. Robertson, E. Greengrass, F. Grossmann, S. Kamenya, L. Pintea, D. C. Mjungu, E. V. Lonsdorf, A. Mosser, C. Lehman, D. A. Collins, B. F. Keele, J. Goodall, B. H. Hahn, A. E. Pusey and M. L. Wilson (2010). “Impact of Simian Immunodeficiency Virus Infection on chimpanzee population dynamics.” PLoS Pathogens6(9): e1001116.
Terio, K. A., M. J. Kinsel, J. Raphael, T. Mlengeya, I. Lipende, C. Kirchhoff, B. Gilagiza, M. L. Wilson, S. Kamenya, J. D. Estes, B. F. Keele, R. S. Rudicell, W. Liu, S. Patton, D. A. Collins, B. H. Hahn, D. A. Travis and E. V. Lonsdorf (2011). “Pathological lesions in chimpanzees (Pan troglodytes schweinfurthii) from Gombe National Park, Tanzania, 2004-2010.” Journal of Zoo and Wildlife Medicine42(4): 597-607.
Why do chimpanzees get into fights with their neighbors? As we report in this month’s Animal Behaviour, one of the major reasons seems to be food.
Since the 1970s, researchers have known that male chimpanzees defend group territories, and that fights between groups can be deadly. But what triggers these fights? Do chimpanzees go looking for trouble? Do they get into fights over mates? Or do they fight over some other resource, such as food? And when they do meet the neighbors, what determines whether they fight or flee? Are they more likely to respond aggressively if they are defending mates, or young infants, or food? Or does strength in numbers matter more? We sought to answer these questions, using 15 years of data on social behavior and ecology.
These data come from the Kanyawara community of chimpanzees in Kibale National Park, Uganda, where I did my PhD dissertation research as a student of Richard Wrangham and Marc Hauser. For the past decade, I’ve been doing fieldwork in Tanzania instead of Uganda, but I’ve continued to collaborate with Richard and his team. Such collaboration is made easier now that the long-term data have been entered into an Access database, and the original datasheets are all scanned, making it a simple matter to consult the original records from anywhere with good internet access.
Working with these data brought back many vivid memories, such as the day I first saw chimpanzees in the wild, back in June 1996. I had come to Kibale to spend a summer doing pilot research. We hiked for hours in the forest to find the chimpanzees, following narrow trails up and down steep hills, stepping carefully along narrow logs lain across boggy patches in the valley bottoms. Everything looked green and wet. Towering rainforest trees hung with vines. Dense stands of wild ginger and other leafy tropical plants crowded the understory.
As we crept along a steep trail, an opening in the trees showed the misty green expanse of the valley below. At last, I caught my first fleeting glimpse of a chimpanzee – I think it was Stout, an adult male – as he crossed the trail. His long black hair glistened with rain as he knuckle-walked calmly but quickly through the forest, looking more like a gorilla than I had expected, having only seen chimpanzees in movies and zoos.
During my first weeks at Kanyawara, the chimps traveled in large parties with many males. I saw most members of the community, including old Lamy, with his crippled foot, new mothers Outamba and Tongo carrying their first infants, matriarch Lope and her family, including the gangly teenager Makoku and young Rosa, grey-bearded Stocky, tough young males Imoso and Johnny, and Big Brown, who was still the alpha male.
During my first few days in the field, the chimps hunted and killed a red colobus monkey, and had a brief, noisy, and (for me) completely confusing encounter with their neighbors, during which the stranger chimps came within sight of us, crashing through the underbrush, displaying at and running towards our chimps before running they turned and ran away. As it turns out, I had come just in time for the last weeks of Uvariopsis season.
Uvariopsis congensis is a small tree that grows in large groves in the understory of the forest. It tends to fruit synchronously, usually in May and June. The fruits are small and red, and look rather like fleshy red peanuts, with two or three seeds.
At Kanyawara, the Uvariopsis groves occur mainly in the southeast of the range, along the border with another chimp community, which has not been habituated. And it turns out that that these Uvariopsis groves are a key focus of intergroup competition.
Back when I was doing my dissertation work, the number of intergroup encounters that had been observed at Kanyawara was still too small for meaningful statistical analysis. But now, in the 15-year dataset, we have records of 120 intergroup encounters. As is typical for chimpanzees, most of these encounters were shouting matches rather than full-fledged fights – chimpanzees gave loud pant-hoots and waa-barks and other calls, challenging their neighbors, and then ran either towards or away from them. But when chimpanzees came close enough to see each other, they were always hostile. Two chimpanzees were killed, and several others badly injured. We found that these encounters happened mainly when chimpanzees visited border areas, especially the southern border.
So why did males visit border areas in the first place? To find mates, when few females in their own community were receptive? To find neighbors to attack, whenever they could gather in big enough parties to have a good chance of beating the neighbors? Or to look for food?
To answer these questions, we needed to use multivariate statistics to consider all these factors at once: mates, party composition, and food. We knew that male chimpanzees were highly motivated to search for mates, and we had previously found that parties that visited the range periphery had more males, presumably because that provided safety in numbers. But we also suspected that food would be an important part of the answer.
Chimpanzees spend most of their time searching for food, eating food, or digesting food. Though chimpanzees eat a variety of things, including monkeys, honey, ants, termites, leaves and stems, they spend most of their time eating ripe fruit from trees. In a tropical forest, the availability of tree fruits varies in a complex way over space and time. Some trees occur in groves in particular areas, whereas others are scattered about the forest. Some tree species, like figs, may produce food throughout the year, but other species fruit synchronously, with a big crop occurring every one or two years. To test how food influences chimpanzee movements, we needed data on both where and when key foods were located.
We had lots of data on feeding behavior. But it could be that chimpanzees travel to different parts of their range for social reasons (such as looking for mates or checking on the neighbors), and just happen to eat whatever they find along the way. So we needed to test whether the feeding data reflected where food was actually located. We therefore examined data from vegetation plots, and confirmed that both feeding data and vegetation plot data agreed that certain tree species were more common in the north, while others were more common in the south. For key species, we also found a good correlation between feeding behavior and independent measures of whether a sample of those trees had fruit in a given month. Additionally, the strong correlation between feeding records and counts of seeds from dung samples gave us confidence that our data on feeding behavior provided a good measure of what chimps were actually eating.
So what did we find?
Males tended to stay closer to the range center, and were less likely to travel to the south, when they were with more sexually receptive females. Party composition also mattered: as we had found previously, chimps were more likely to visit dangerous border areas when in parties with many males. And as we suspected, food had a big impact on chimpanzee movements. They visited the southern border mainly when southern fruits were in season. One species in particular had a strong effect on encounter rate: Uvariopsis. Most of the intergroup encounters took place in the southeast, in or near the Uvariopsis groves, and encounters were more likely to occur on days when chimps spent more time eating Uvariopsis.
So chimpanzees at Kanyawara visited borders for various reasons, but food seemed especially important. In particular, a good crop of Uvariopsis attracts chimps from both sides of the border, resulting in a spike in the rate of intergroup encounters during Uvariopsis season.
When encounters did occur, though, we found that the response depended mainly on the number of adult males that were present. Whether they were with mates, infants, or food didn’t matter as much as whether they had enough males to put up a good fight. These results were very much in line with what we had previously found with the playback experiments.
So is food generally the main driver of intergroup competition in chimpanzees? I’m currently working on data from Gombe to test whether similar factors apply there. It seems likely that in addition to food, the relative power of communities is a key factor. An interesting case in point is just 12 km from Kanyawara: the Ngogo community, studied by John Mitani and David Watts. This is the biggest chimpanzee community ever studied, with about 150 members. These chimps live in a range about the same size as Kanyawara’s, but in higher quality forest, with a lot more food, and three times the chimpanzees. And a lot more violence. The Ngogo chimps frequently patrol their boundaries, and in a ten-year period, Ngogo males killed 21 of their neighbors.
While the Ngogo chimps were killing their neighbors and expanding their range, the Kanyawara chimps were losing territory to their powerful southern neighbors (a group of unhabituated chimpanzees whose range appears to be sandwiched between Ngogo and Kanyawara). By 2006, the Kanyawara range was less than half as big as it had been in 1998, and the southern chimps had pushed the boundary a full kilometer north. It may be that chimps in a powerful community, like Ngogo, are more likely to go looking for trouble, whereas chimps in a weak community, like Kanyawara, visit dangerous border areas only when the abundance of food there makes the risk worthwhile.
After starting this blog in August, I hardly blogged at all during the semester. Partly this was because with my teaching and other duties, I had little time to spare for blogging. And in what spare time I did have, I wasn’t thinking about blog topics. I was thinking about my Mom, who was fighting what turned out to be a losing battle with leukemia.
Years ago, as the stem cells in Mom’s bone marrow were going about their usual business of dividing to make cells that would in turn give rise to new blood cells, one of them made a mistake. A deletion occurred on Chromosome 9. That cell divided and gave rise to a whole lineage of cells with the same deletion. Over time, some other cells in that lineage arose with additional genetic errors that prevented them from making proper blood cells. Instead, they produced millions and millions of daughter cells that filled up Mom’s marrow with useless cells, crowding out the good cells.
Mom only became aware that there was a problem a couple of years ago, when she was diagnosed with Myelodysplastic Syndrome (MDS), which often develops into leukemia. And in Mom’s case it did. In March, on her birthday, she was diagnosed with Acute Myeloid Leukemia (AML) and soon started her first round of chemotherapy.
Mom faced all of this with remarkable courage. In the hospital, she joked, made light conversation, took photos of all her visitors, and kept her good humor through all of the indignities of hospital life – the flimsy gowns, the lack of privacy, the constant parade of people coming into the room to do this or that, the increasing need for other people to help with basic bodily functions. Mom accepted all of this gracefully. Though she did not like revealing her birth year to other people, in the hospital many times a day she cheerfully gave her name and birthdate to hospital staff, as required when receiving new medications or blood transfusions. She always liked to look her best. When the chemo caused her hair to fall out, she wore wigs and hats – but mainly to make her visitors comfortable. Over Skype, she asked us if we wanted to see the bald head, and showed us when we said yes, seeming entirely cheerful and matter-of-fact about the loss of the hair that she had been so careful to keep just so over the years.
As a family, we tried to learn as much as we could about Mom’s condition and treatments. Dad bought and diligently read a medical textbook on hematology. This information was interesting enough, and helped us understand what Mom was going through, but we never found what we were looking for: some hidden nugget that would help Mom live. And the scientific literature was far from comforting. Studies of AML (such as here and here) found that for most patients, even with the best treatments available, life expectancy was a matter of months rather than years, especially if they were older, had a background of MDS, and had multiple detectable genetic changes in their chromosomes.
I’m not sure what I imagined chemotherapy would be like, but the actuality was both more peaceful and more awful than I had expected. For the most part, it involved just waiting in the hospital room, attached to a rack full of IV bags dripping an array of different fluids, including saline solution, blood, plasma, and chemotherapy drugs, into a PICC line – a tube inserted into the arm that directed the incoming fluids right to the heart. At first, it hardly seemed like Mom was really sick. She was just like she always was, except confined to a hospital room and attached to an IV drip. But gradually the chemo did its job and took its toll, and Mom got sicker and sicker.
One of the chemotherapy agents that Mom received was Cytarabine. This is chemically nearly identical to cytosine, one of the four bases that make up DNA. It is similar enough that it gets incorporated into new DNA, but different enough that that new DNA doesn’t work properly, and the new cells die as a result. So all the rapidly dividing tissues – cancer cells, but also hair, skin, and the intestinal lining – suffer as a result, resulting in all the usual chemotherapy side effects.
Another chemo drug Mom had was Daunorubicin – a ruby colored compound isolated in the 1950s from soil-living fungus in Italy and named for a pre-Roman tribe, the Dauni. The bright ruby color of this drug made it look especially potent and menacing when it was injected. Daunorubicin molecules are just the right shape to slip in between successive base pairs in DNA strands, unwinding the DNA a bit and interfering with replication. Again, this wreaks havoc, not just on cancer cells, but also on all healthy tissues that rely on rapid cell division.
Mom endured two rounds of chemo, achieved remission, and came home, where before long, life almost seemed back to normal. She cooked dinners, played bridge, went to church, and even traveled across the country to see her newest grandchild. It started to seem that Mom was healthy and out of danger.
However, while the chemo had killed a lot of cells, it hadn’t completely wiped out the mutant stem cells. Instead, the few surviving mutant cells continued to replicate, acquiring new mutations on the way. By September, the leukemia was back, and just before Thanksgiving, it took Mom away from us.
The chemo took a terrible toll, but without it, what happened in November would have happened in March. Thanks to the chemo, Mom had a summer at home, visits from her children and grandkids, and time to say goodbye.
Mom wanted to live, but during what turned out to be her final hospital stay, she talked of how the quality of life, and the prospects for improving it, diminish. In one of our last conversations, she told me, “I had hoped to live long enough to see how things turned out for everyone. But then, even if we lived to be over 100, we would still want more.”
Mom was one of the very best people I have ever known, and it seems terribly unfair that she should be taken from us so soon. It’s hard to believe that such a vibrant person, so full of love and caring and thoughtfulness, the keeper of so many family memories and traditions, should be undone by the information copying errors of the tiny, mindless cellular machinery of her own body.
Around the time Mom got sick, my computer crashed. The Genius at the Apple Store said it was a problem with the logic board, and that there was really nothing to be done, since the repairs would cost about as much as a new computer, and that in a computer of such advanced age (nearly five years old!), more problems would soon be arising. Luckily I had my data backed up, and almost all the files on my old computer are now on my new computer. But Mom is gone. There’s no backing her up.
Religious minded people will be tempted to provide reassurance that Mom is in Heaven. That’s certainly what Mom believed, and if such a place exists, then surely she is there. But my own inclination is to think that we are material beings, and that our lives begin and end on earth. This materialist view provides its own comforts. “No Hell below us – above us, only sky.” There is no one to blame for the loss of loved ones: it just happens. But whatever one believes about the metaphysical, Mom left behind a great big hole here on earth.
With the start of the semester, I’ve been too busy teaching to write new posts for the blog, so lately, the site has served only to attract spam.
Some of these spam comments are quite cunning. They usually involve some sort of flattery. Here’s one example:
“Saved as being a favored, I truly like your weblog!”
I was fooled into thinking this was a real comment at first. Then I got an onslaught of similar comments, such as:
“Nice post. I learn something more challenging on different blogs everyday. It will always be stimulating to read content from other writers and practice a little something from their store. I’d prefer to use some with the content on my blog whether you don’t mind. Natually I’ll give you a link on your web blog. Thanks for sharing.”
“I just now adore to learn different themes within you blog page.”
“This article ahceived exactly what I wanted it to achieve.”
“Son of a gun, this is so hlepufl!”
That’s the hook. Softened by flattery, the blogger allows the comment to be posted. Now comes the benefit to the spammer: the comment includes the spammer’s URL – which is always some commercial site that they want you to visit. So it’s a cheap way to manipulate blogs into providing free advertising.
It’s annoying to get message after message that just turns out to be cleverly disguised spam (“Lobster Thermidor aux crevettes with a Mornay sauce served in a Provençale manner with shallots and aubergines garnished with truffle paté, brandy and with a fried egg on top and spam!”).
But it’s also quite a nice example of manipulation in the evolution of a communication. As Dawkins and Krebs have argued, from an evolutionary perspective, we would expect communication mainly to involve attempts to manipulate others. The signaler tries to get the listener to do something for the signaler. My baby fusses, for example, because she wants me to carry her, or she wants her diaper changed, or wants to be fed. She wants something, and she can get it from me by making signals that I simply can’t ignore. Of course, with my baby, I don’t mind the manipulation, because she’s my baby. But the spambots with bad spelling and mangled grammar – those I could do without.
Reading the news these days, one might get the impression that evolution is just for Democrats, not Republicans. For example, in a recent (23 August 2011) post for the Washington Post, Richard Dawkins calls Republican Governor of Texas a “fool” and an “ignoramus” for expressing some doubts about evolution, and implies that these labels apply to anyone voting Republican. The next day (24 August 2011), Ann Coulter published her own post, calling Richard Dawkins “retarded” and trotting out a series of tired old arguments against evolution.
Coulter is just plain wrong on evolution. At the same time, though, Dawkins is wrong to disparage the political opinions of people who happen to vote Republican.
Coulter is wrong about evolution in many ways. For example, she claims that if “Darwin were able to come back today and peer through a modern microscope to see the inner workings of a cell, he would instantly abandon his own theory.” Darwin, however, spent many years peering through microscopes at the inner workings of barnacles, and it was the fascinating complexity of their anatomy that deepened his understanding of evolution. Modern understanding of the inner workings of cells has further deepened scientific appreciation for how evolution works. The patterns of DNA encoded within each living cell have confirmed Darwin’s insight that every living thing on earth is part of one big family, the Tree of Life.
The Tree of Life
Comparing the similarity of DNA sequences has revealed some interesting surprises – for example, humans and chimpanzees are closer kin than chimpanzees and gorillas, even though gorillas look basically like giant chimpanzees – but has also generally confirmed the big picture of the tree that would be expected from shared descent with modification: humans and chimps are twigs on the primate branch, sprouting from the mammalian limb, emerging from the great trunk of vertebrate life, which near the roots of the tree joins with other great trunks and side branches: fungi, plants, and a variety of different bacteria.
Similarly, Coulter brings out the old argument from probability theory, that “it is a mathematical impossibility, for example, that all 30 to 40 parts of the cell’s flagellum – forget the 200 parts of the cilum! – could all arise at once by random mutation.” But as Dawkins clearly explains in The Blind Watchmaker – which Coulter doesn’t seem to have read, or at least not understood – evolution doesn’t throw together everything at once. Evolution works with small gradual changes, building on what exists already. It would indeed be statistically highly improbable to throw even a small number of things together at random and have them work together at all, much less well. But evolution doesn’t do that. Instead, evolution blindly, mindlessly tinkers with what already exists, changing a little bit here and there at random, and then lets these different variants fight it out in the arena of natural selection.
Coulter has made a career of strident political writing, and while the tone of her piece may be more appealing to those who already agree with her than persuasive to her opponents, it is at least consistent with her genre. Richard Dawkins, however, is a scientist. Indeed, he is one of our clearest thinkers and writers on evolution. It is disappointing that he here conflates views on evolution – which he rightly calls a scientific fact – with views on politics – which are, after all, opinions.
We have abundant evidence from fossils, geology, genetics, molecular biology, physiology, development, biogeography, and numerous other fields of study that evolution has occurred and continues to occur all around us. In contrast, while political opinions bear some relation to facts, they nevertheless pertain mainly to matters about which people with intelligence, experience and expertise continue to debate vigorously. Political questions are generally much more complicated and harder to be sure of than questions in the natural sciences, and they often relate to values – what people care about – rather than things that can be objectively determined to be true or false. Many political questions concern economics – which is routinely insulted as “the dismal science” because economists have such a great diversity of opinions. And why is economic opinion diverse? Is it because economists are more stupid or quarrelsome than other academics? Or is it because economies are just incredibly complex and difficult to understand?
Contrary to what readers of Coulter and Dawkins might be led to believe, evolution is not just for Democrats. The scientific truth of evolution doesn’t depend on a person’s political affiliation. People with all sorts of different political views have made important contributions to evolutionary theory. The great population geneticist J.B.S. Haldane was an idealistic Marxist and from 1937 to1950 a member of the Communist Party. Haldane’s colleague Ronald Fisher, described by Dawkins as “the greatest biologist since Darwin,” was politically conservative. Nobody today much cares about Haldane’s or Fisher’s political views. It’s their scientific ideas that have survived the test of time.
Darwin’s own political views might be hard to categorize today, because political views change greatly over time. Darwin shared Lincoln’s exact birthday (February 12, 1809) and Lincoln’s abhorrence of slavery. Maybe, if Darwin had been American, he would have voted Republican. I don’t know. But we don’t remember Darwin for the stances he took on the pressing political issues of his day. We remember him for his idea of evolution by natural selection, which remains just as powerful today as it was 150 years ago, and will continue to be so 150 years from now, or 150 thousand years from how, when the political issues we care so much about today will long be forgotten.
Indeed, evolution by natural selection will necessarily occur wherever life exists in the universe. If intelligent beings exist on a planet orbiting, say, Alpha Centauri, we can be sure of two things: (i) life on their planet undergoes evolution by natural selection and (ii) the question of whether to vote Republican or Democrat will be entirely, er, alien to them.
