That is not a freak accident. That is what volcanoes do.

It is erupting now. Evacuations have been ordered. Here is some amazing footage:

It is probably not a coincidence that two of the three subspecies of gorilla live within sight of each other (and of the main subspecies, the lowland gorilla) within this region. The Virunga volcanoes are not old enough to have supported island forests for the evolution of these specific subspecies, but other highlands in the region, or other volcanoes (perhaps in the Eastern Rift) may well have been the location in which they evolved.

And, as it turns out, there is reason to believe that the split between chimps and humans occurred on one of these volcanic mountain tops several million years ago. Or, at least, in an environment geologically similar to the upper reaches of the Virunga Volcanoes. But to tell this story right, I have to go back a few years.

… distant in the background African sounding drum music, distant thunder, polyphonic singing fades to the sound of steel on rock as dozens of workers are excavating elephant bones in the dusty windswept African plain under the watchful eyes of the Rwenzori …

The Congo. Parc National de Virunga, well north of the Virunga Volcanoes, north of Lake ex-Edward. I was with a fairly large expedition. At the time we had been waiting for crucial supplies, including tents and cots and other accouterments of field life, to arrive in a truck the expedition had purchased in Kinshasa, which was being driven to the field site via the Central African Republic (there are no roads that traverse the Congo). The truck was several weeks late. So, on the occasion that we heard a vehicle on the nearby park road (once or twice a week), we had taken to chanting the name of the driver of the truck (Leo) while facing a mock-up of the truck made by a local school kid, that we had placed in a makeshift shrine under a tree near our dining area.

“Leo… Leo…. Leeeeoooooo….” we were chanting one day, in observance of our cargo cult, as we heard a vehicle driving down the road, well out of sight to the east.

When the sound of the vehicle suddenly shifted, with gears lowering, near the juncture of the main park road and the side road leading down to our research site, we didn’t think much of it. The large muddy puddle at that spot caused all vehicles to down shift and slow. But this time, the vehicle in question stayed in low gear and we could hear it getting slowly closer to us… this truck had turned in to the research camp road! It was Leo! Leo had arrived with the tents and cots and the garlic and the other stuff!

But when the vehicle finally came in sight after traversing the 3 kilometer path that lead to our camp, we were very disappointed to see that it was not The Truck driven by Leo with Our Stuff. Rather, it was someone we did not know in a Land Rover.

Visitors.

The visitors turned out to be a chimpanzee conservation specialist on contract with the United Nations and her driver. She was on her way south to the Virunga Volcanoes to habituate the chimpanzees in one of the mountain top forest patches to tourism. That is similar to habituating the chimpanzees to researchers, but instead of wearing khaki’s and carrying around notebooks … so the chimps get used to that … you wear loud print Hawaiian shirts with cheap cameras hanging around your neck and carry tour books and gin and tonics. So the chimps get used to that. I assume.

Anyway, the chimp conservation specialist eventualy moved on and went to the Virungas. I eventually (several months later) moved on and went to Cambridge Massachusetts, where I lived at the time (plus or minus) when I was not in the Congo.

And my first night in Cambridge had me crashing at the home of Irv DeVore, my advisor, the famous primatologist and forager researcher. Also crashing at DeVore’s was Richard Wrangham, famous primatologist who at the time was being courted by Harvard, and was thus visiting from Michigan.

Richard and I had a conversation. It turns out that he had met up with the UN chimpologist in the Virungas at some point when I was at the other end of the park (this park is big … traversing it the long way is not normally done, but when it is it can take a couple of days and you quite seriously risk your life). This led to an interesting conversation.

Richard and I started to exchange information and ideas. I had been looking at the use of roots by foragers in the Ituri Rainforest, and Richard had found out something interesting about the Virunga chimps:

The upper slopes of the volcanoes have porous soils and rock, and no habitual lakes, ponds or long-lived streams. Water falls from the sky and disappears beneath the surface of the volcano, to come out near the base of the mountain as springs, but in the main not accessible for drinking by the denizens of the high forest itself. Animals that live in the forest get their water mainly from very short lived puddles on the surface or from tree crotches, where branches separate and tiny puddles form, and possibly from canopy plants that hold water. During the two month dry season these sources of water dry up and any animal that requires daily drinking must migrate out of the forest or die.

But the chimps, who do require daily access to water, don’t migrate out of the forest. They can’t. The habitat they live in is circumscribed and can’t leave. Well, individual chimps probably do leave now and then and some of them manage to find other suitable chimp habitats, but for the most part the chimps are trapped in a habitat without drinkable surface water for seven to ten weeks or so per year.

It turns out that the plants that live in this habitat are also water stressed, and some of them have interesting evolved adaptations to this. One viney plant, a kind of yam, has evolved a huge underground storage organ that swells as it collects water all year, then provides water during the dry season.

This yam is about the size of a coffee table or maybe a small couch. That is quite large for a yam. And it is loaded with water.

And … you guessed it: The chimps dig these tubers up and drink from them during the dry season.

This may or may not impress you but it should. Of all the species of vertebrates, hardly any use roots of any kind for any reason. Probably only mammals. Of mammals, bears, pigs, and rodents include species that use roots to some extent. Among primates it is not generally thought of as a major adaptation. Nearly 300 species of primates have fewer than four or five (including these chimps and humans) that ever use roots. And these chimps are the ONLY chimps known that dig for roots.

There is a lot more to this story than the Virunga chimps or my work with foragers in the Ituri. There is work by other people on pigs and bears, there is work by my friend Betsy Burr on rodents, and there is information from the fossil record. But the conversation I mention above at DeVore’s house led, after considerable time dicking around with it, to this: The rise of hominids as an adaptive shift in fallback foods: Plant underground storage organs (USOs) and australopith origins. In which:

We propose that a key change in the evolution of hominids from the last common ancestor shared with chimpanzees was the substitution of plant underground storage organs (USOs) for herbaceous vegetation as fallback foods. Four kinds of evidence support this hypothesis: (1) dental and masticatory adaptations of hominids in comparison with the African apes; (2) changes in australopith dentition in the fossil record; (3) paleoecological evidence for the expansion of USO-rich habitats in the late Miocene; and (4) the co-occurrence of hominid fossils with root-eating rodents. We suggest that some of the patterning in the early hominid fossil record, such as the existence of gracile and robust australopiths, may be understood in reference to this adaptive shift in the use of fallback foods. Our hypothesis implicates fallback foods as a critical limiting factor with far-reaching evolutionary effects. This complements the more common focus on adaptations to preferred foods, such as fruit and meat, in hominid evolution.

I don’t think this happened in the Virungas, because as I mention above, they are relatively young volcanoes. It may even be that nothing like this happened at all. The significance of the observation may be simply that chimps can make use of USOs. The last common ancestor of humans and chimps was probably a lot like a chimp. So, the Virunga chimps simply demonstrate that this early population may have been able to use roots for something (water or food) and further demonstrates that the use of this resource could be not only something that some groups use, but that a particular group can survive because of. That is important because of all the interesting things chimps do, like using tools to get termites or various “symbolic” behaviors to communicate, none are done by all groups of chimps, and most or all of these behaviors seem to come and go randomly and do not have a high impact on survival. But the root digging and drinking of the Virugna chimps can’t disappear as a strategy in this one group; They depend on it for survival.

It is also not certain that such a context (a truly dry two months or so per year) requires volcanic sediments, but this does seem like a very likely location for such a thing. A similar thing happens on the Kalahari sand sheet, where water is abundant, but only if you are able to get at the water which is meters, or tens of meters, below the surface. However, I am pretty sure that there is not a huge water-abundant tuber of this type in th Kalahari. But perhaps at one time there was.

Evolving away on the upper slopes of a volcano would have other effects a well. Like, unfortunately, occasional local extinction. Of course, it would also be a great place to “discover” fire … But that is an entirely different story, for another time.

Recent Kenyan Newsreel:

Earlier film on the Nyiragongo volcano (near Nyamuligira) and the region:

LADEN, G., & WRANGHAM, R. (2005). The rise of the hominids as an adaptive shift in fallback foods: Plant underground storage organs (USOs) and australopith origins Journal of Human Evolution, 49 (4), 482-498 DOI: 10.1016/j.jhevol.2005.05.007

Have a look at the following map:

This map is about 130 km wide (80 miles) and 275 km high (170 miles).
The location of Nyamuragira is indicated by the red arrow. Notice the discontinuous but rather impressive ridge that runs from the lower left corner of the map to nearly the upper right corner. That is the western wall of the Western Rift Valley. The volcanoes just south of the middle of of the map are all within the rift valley. The eastern margin of the valley is poorly defined in this area (it is often the case with rift valleys that one side is better defined than the other).

The two lakes were formerly one lake, and have become separate because of uplift and lava infilling caused by the Virunga Volcanoes, in what is an ongoing process. Several of the volcanoes in this region are active, and there are frequent earthquakes and various eruptions. You can learn about these volcanoes in more detail elsewhere, but here I can give you some broader context regarding the biology and culture history of the area.

To the west (left side of map) on the ridge above the rift valley there are roads linking a number of small villages, agricultural areas, and cities, and in recent decades this has been a fairly heavily populated area. To the west of this is the Central African Rain Forest, sparsely populated. To the southeast (lower right hand corner of the map) is Rwanda, which is heavily populated and has much of its land in agriculture. The valley of the rift is very sparsely populated. This is in part because the valley floor is conducive to the tse tse fly and concomitant sleeping sickness as well as malaria and other diseases. Following a series of late 19th century and early 20th century epidemics (and some warfare) the region was depopulated by colonial authorities and turned into a combination park and buffer zone. Here and there in the valley are plantations or settled areas, but many of the flat areas you see here, as well as north of Lake ex-Edward were wild parkland, only sparsely inhabited at the time the parks were formed.

The borders have been buffer zones in part because of long term distrust and tension between the countries. Rwanda was part of Congo, and administered by the Belgians, but tribally Rwanda has had a complex relationship with the Congo. Rebels operating in the Congo under Mobutu were given refuge in Tanzania and Rwanda, various Tutsi or Hutu linked groups have operated in the Congo, and so on, for many decades. The Ugandan-Congolese relationship is partly tribal but also Colonial. The British colonies (including Uganda) were run very differently than the Belgian colonies, and one result of this was a state of ongoing small scale warfare in parts of the Congo, really from the time of early European exploitation of this area under Stanly through to the present, with a few notable decades of peace here and there. Uganda, on the other and, experienced less of this small scale warfare. This meant that a border was useful to the colonial administers for a number of reasons, and it has been treated as a military resource. In addition, north of Lake Edward there is a tribal link between the ethnic group represented by former evil dictator Idi Amin (Lake Edward was called Lake Idi Amin at one point in time!), with this tribal affiliation running across the border. The nature of the tribal linkage is very complex (one of the more obscure and complex ethnic complexes in Africa). When Amin took over Uganda in a coup, troops from the Eastern Congo, including one man I worked with in the Congo (whom I refer to as JP) went with Amin (JP was the door gunner on the helicopter Amin used to fly to Kampala during the battle.) Later, when Amin was forced out of power in 1978, the machinery of a large part of his army ended up in the northern and western region of this map (along with divers, troops, and other refugees). So during the time I lived in this region, there was a certain background noise of left-drive vehicles and British auto parts dating to a certain time period.

Subsequent to the beginning of the ongoing Congo War and the Rwandan Genocide in the early 1990s and up to the present, there were major disruptions of populations, with villages and cities emptied out or filled with refugees, areas of the parks overrun by various armies and refugee camps set up at numerous locations, with more or less constant fighting going on at some level somewhere on this map in any given year. You have heard of the millions of people who have died in the Congolese war? Look at this map. Many of them died here or very near the margins of this map, which represents a plot of land roughly the size of the US state of Maryland, or between Belgium and Switzerland in size. (Kigali, the Rwandan capital, is just off the map.)

The uplands in this region are either forest or converted to agriculture, and the lowlands are savanna with extensive grasslands and interspersed woodlands. The Volcanoes, since they are mountains rising from the planes, are often islands of rain forest surrounded by grassland. For this reason, they are evolutionary laboratories, and many endemic species live in these forest patches. It is probably true that the mountain gorillas of the region evolved into a subspecies separate from the lowland gorillas and the graueri gorillas because of this island effect. Indeed, the home ranges of all three of these subspecies touch only in the region represented on this map, with the region of the graueri gorillas being entirely included in this map on the western edge of Lake Edward … assuming that this rare subspecies continues to exist at all.

You may have heard of the chimpanzees that are threatened by this lava flow. The mountain chimpanzees of the Virunga region are very important for a couple of reasons including the fact that their isolation from other chimp populations makes them an interesting laboratory for the study of genetic and cultural isolation in a hominoid other than humans. Too bad very little is being done in this area.

But these chimpanzees have yet another point of interest relate to research, including research I’ve been involved in and that you’ve likely already heard a bit about. This has to do with the split between chimpanzees and human ancestors.

And I’ll tell you about that in the next post.

Mount Nyamulagira, 25km (16 miles) from the eastern city of Goma, erupted at dawn on Saturday, sending lava into the surrounding Virunga National Park.

About 40 endangered chimpanzees and other animals live in the area.

But the country’s famous critically endangered mountain gorillas are said to be safe as they live further east.

source

These are very special chimpanzees. I believe I’ve blogged about them elsewhere, but I’ll write new something about them soon.

I’ve driven though this range of volcanoes, and flown over them as well.

Erik has details here

Redoubt is WSW of Anchorage, Alaska but is otherwise, I think, pretty isolated.

Keep an eye on it here and here, via web cam.

Good thing someone is keeping an eye on these volcanoes!

The paper reporting this, in the current issue of Science, concludes:

The caldera-wide accelerated uplift reported here is interpreted as magmatic recharge of the Yellowstone magma body. Although the geodetic observations and models do not imply an impending volcanic eruption or hydrothermal explosion, they are important evidence of ongoing processes of a large caldera that was produced by a super volcano eruption.

A little vague. I’m pretty sure, from my reading of this paper, that there is not a major imminent danger. But it is interesting to contemplate the magnitude of these things.

This volcano, the volcano we affectionately know as “Yellowstone National Park” (the caldera takes up something like a third of the park area, and is entirely enclosed within it) last erupted in a big way about 600,000 years ago. That was the third in a series of “giant eruptions.” Subsequently, there were several smaller volcanic eruptions, the most recent being about 70,000 years ago.A caldera is a hole left behind when a very large and explosive volcano blows everything out more or less at once. As calderas go, Yellowstone is on the list of the largest known. Here is a rough outline of the Yellowstone Caldera very approximately superimposed over New York City:Here is a little historical perspective, a list of exenmlar volcanic eruptions of this type (leaving a big caldera, ejecting lots of stuff).

Tambora, Indonesia

192 years ago, a mere 30 or 40 square km in area, ejected about 100 cubic km of stuff.

(About ten other similar sized eruptions have happened during the last 10,000 years, Tambora possibly being the largest.)

Toba, Sumatra

71,000 years ago, about 3,500 square km in area, ejected about 2800 cubic km.

Yellowstone

600,000 years ago about 4,000 square km in area, about 1,000 cubic km ejected.

La Garita, Colorado

28,000,000 years ago, about 2,600 square km in area, about 5,000 cubic km ejected (possibly the largest volume of any known volcano)

So, as you can see, the Yellowstone Volcano was a doozie. Comparatively speaking._______________Source:

Chang, W., Smith, RB., Wicks, C. et al.. (2007). Accelerated uplift and magmatic intrusion of the yellowstone caldera, 2004 to 2006.. Science 318, 952-956.

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