The reason that most “wasabi” is fake, and the agronomy and chemistry of wasabi, turn out to be really interesting.

Here is the background info references in the video.

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

Much is made of the early use of stone tools by human ancestors. Darwin saw the freeing of the hands ad co-evolving with the use of the hands to make and use tools which co-evolved with the big brain. And that would make the initial appearance of stone tools in the archaeological record a great and momentous thing. However, things did not work out that way.

It turns out that up-rightedness (bipedalism), which would free the hands, evolved in our ancestors a very long time (millions of years) prior to our first record of stone tools. The earliest upright hominids that are definitely human ancestors probably emerged either close to five million years ago or close to seven million years ago, depending on which of the current evidence you like and how you interpret it. The earliest chipped stone tools are a little over 2.5 million years ago.

Furthermore, at that time there was not necessarily any real increase in brain size. Maybe a little in one or two hominid lineages, but it is not clear which hominid lineage(s) were making stone tools in relation to the brain size and the increase in size is unimpressive to the extent that it is probably safe to say that as more fossils are found and more data analyzed it could go away.

It is true that about the same time stone tools show up (give or take a couple/few hundred thousand years) there may have been an increase in species of hominds, and/or an increase in some of the features that they shared, such as whopping big teeth and the skeletal and muscular aparatus to use those teeth. But it is also true, as Alison Brooks and I have shown in various analyses, that it is just as likely if not more likely that the appearance of stone tools in the archaeological record at that point in time is a function of how the arcaheoligcal record is formed. We beleive that it is fairly likely that chipped stone tools were already in use and simply became visible to us at this point. Maybe.

Which brings us to some very serious speculation, but what the heck: I think that what it takes, mentally or neurologically, to make this early, relatively simple stone tool technology is well within the range of capacities I can imagine for a chimp-like hominid. True, modern chimps have a hard time making stone tools, but their “hands” are not “freed” like a more bipedal hominids’ hands would be. The mental/neurological part is not so hard. In a series of experiments some years ago, started by Glynn Isaac, we had many dozen Harvard Undergraduates, who had no prior exposure to stone tool manufacture, bang rocks together (in isolation) for the sole purpose of making sharp edged pieces. All of them managed to replicate most of the products in a typical Oldowan industry in just several minutes. The collection of any dozen or so of these students’ produce includes all of the Oldowan “tool” forms.

The Oldowan is the outcome of breaking rocks.

As to the impact that Oldowan style technology would have on the life of a chimp-like human ancestor? This would probably be as important as any other single aspect of foraging strategy. I imagine they were mainly making sharp edges in order to sharpen sticks, or to cut into things (or both), which would have increased the range of possibilities for accessible foods at the same level that, for instance, cooperative hunting that we see in the Tai chimps of West Africa. Important. Not necessarily overwhelmingly important.

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

Chimps dig up clues to human past? from PhysOrg.com
One of the keys enabling the earliest human ancestors to trade a forest home for more open country may have been the ability to gather underground foods. Now a team of scientists reports for the first time that in Tanzania our closest living relatives, chimpanzees, are using sticks and pieces of bark to dig for edible roots, tubers and bulbs.[…]

The evolution of human diet followed a major zig (as in zig-zag) in a wholly unexpected direction, followed by the most significant biological innovation to ever occur among multi celled animals: The invention of cooking. I’m actually going to point you to two papers on this topic, and provide a brief summary of the ideas here.

Let’s start with the bold assumption that humans evolved from a chimpanzee-like animal. This is tantamount to saying that the last common ancestor of chimpanzees and humans was, essentially, pretty much like a chimpanzee. At another time, I’ll write a post on why this is a good assumption, but for now lets just go with it. Some large percentage of human evolution experts like this assumption, a bunch of others hate it (which is the usual pattern for most ideas in human evolution).

A mammal’s diet is reflected in physiological attributes that can be discerned from the fossil record. Body size, the nature of the teeth and associated muscles, possibly the shape of the mouth’s cavity, and even the overall size and shape of the gut may be closely connected with diet.

If we draw a direct line from a presumed chimpanzee-like ancestor to modern humans, we can make some inference about dietary changes by looking at these features. Chimp and human teeth are fairly different at first glance. Chimps have large canines, which could influence chewing, but let’s ignore that for now and assume that the loss of fighting canines is related to something else. The shape of the tooth row is different, with Chimps’ molars being roughly parallel, while human teeth form a more continuous arc. That probably has noting to do with diet and more to do with the canines and their use in a somewhat elongated snout (and some changes in human skulls). Chimp teeth are relatively thin on enamel and they are not especially high-cusped or large. This is not too different from human teeth. In other words, it is hard to look at the molars of chimps and humans and speculate about huge differences. The incisors of chimps are very large compared to humans, and that is likely to be a dietary difference. The large incisors are thought to be useful in processing fruit, both for biting into hard fruits and for keeping the wadges of tough fibrous fruit into the mouth during prolonged bouts of chewing.

Humans range in size from about chimp-size to much larger. This mean that humans have a higher demand for energy for both growth and maintenance of the larger size, which in turn would place more demands on the human diet (in terms of total energy). Chimp guts seem to be larger relative to body size suggesting that chimps eat a lower-quality food that requires more processing in the gut.

But why compare chimp and human indicators of diet when we can actually observe chimp and human diets? No good reason, actually, other than to prepare the groundwork for comparisons that cannot be made by direct observation (the diets of extinct hominids).

Living chimps like to eat fruit, and they eat what is known in the biz as “Terrestrial Herbaceous Vegetation” (hereafter: THV) as a fall back food when fruit is not available. Forest salad is better than starving. Chimps also eat some meat. But what does the typical human diet consist of?

This is a problem, because as we look at different human populations, we see a huge amount of variation. One way to make sense of the diversity of human diets is to start by only considering the diets of hunter-gatherers. But among hunter-gatherers, there is still a huge range of diets. Some human forager groups eat almost all meat, others eat very little meat, for example. OK, so we can simplify this even more by focusing on human hunter-gatherers who live in tropical and subtropical regions, since people have moved into temperate and colder regions only several thousand (or tens of thousand) of years ago. But we still encounter a large amount of variation. With respect to meat eating, we’ve only eliminated the most extreme cases such as the Inuit.

One thing that obviously sets human diets apart from all other mammals is that a very large percentage of the food that humans eat is cooked. This is important. Consider these two probable facts:

1)An important percentage of the food that all human groups consume is cooked and can only be eaten if cooked; and
2)Many environments in which human foragers live or have lived provide food that is insufficient for human sustenance unless it is cooked.

In other words, not only do we eat a lot of cooked food, but without that cooked food there are probably many regions of the world where our species would simply not survive.

Putting it yet another way: The ability to cook food transforms most environments on this planet into one habitable by humans. THIS is a link to a paper that suggests that the origin of cooking (which involved the controlled use of fire) is indicated in the fossil record by a strong biological signal. This signal consists of a huge increase in body size accompanied by an impressive reduction in tooth size. These two changes are at odds with each other: How do you manage a huge increase in energy requirements for growth and maintenance at the same time as a decrease in the basic apparatus for obtaining energy? There are other physical changes as well, and broad implications including changes in mating system, suggested in our paper. Enjoy!

Above, I talked about drawing a straight line from a chimp like ancestor to modern humans, but many of you knew that I was just leading you on. You know this because one of the major findings of the last 35 years of human origins research is that our lineage has undergone change not in a single direction (leading to “us”) but rather in various different directions at different times. The key characteristic of the rise and diversification of the australopiths and their close relatives was probably NOT becoming bipedal. Oh sure, that was important and everybody goes gaga over that interesting fact. But the most important adaptive innovation was probably megadonty and related adaptations. This involved the surfaces of the teeth becoming larger, the enamel thicker, and teeth that are normally not used in chewing being recruited to varying degrees to doing the job of the molars (along with the giant molars themselves, of course).

Concurrent with this was NO change in body size (at least none that follows any sensible pattern); a probable increase in sexual dimorphism indicating a mating system shift from something like a living chimp (multi-male multi-female) to something more like a gorilla (single reproductive male and a harem of females), as well as some other details like a larger mouth interior signaled by a high arching palate.

Again, I’m going to send you to a paper, which you can download HERE. In this paper, we argue that the primary novel adaptation of these australopiths was the use of plant underground storage organs (roots and such) as the principle fall back food. In other words, a chimpanzee like ancestor, forcing on fruit as it’s primary food and THV as it’s fall back food probably continues eating fruit (and some meat, we suppose) but changes it’s fall back food from leaves to roots.

There are many important implications of this, some speculation some not. For instance, there are more roots in drier environments. As you measure root availability from the rain forest, wooded savanna, open savanna, and arid areas, you get more and more as you move along a transect from wetter to drier habitats. A chimpanzee like animal would be confined to the rain forest not only because its primary food (fruit) is more abundant there, but perhaps more so because it’s all-important fall back food … the food it eats to avoid starving in a bad season or year … is confined to the rain forest. Chimps would not be able to eat most of the non-rain forest plant leaves. But if you swap roots for THV, it is now actually preferable to leave the rain forest to seek this fall back food.

The eating of USOs as a fall back food essentially served as a kind of conveyor belt moving these hominids from the rain forest into other, more open biomes. We suspect it shaped social structure and behavioral ecology of the australopiths as well. In some way, it could be said that these early hominids were more different from either chimps and humans than humans and chimps are to each other (… hey, I said SOME ways…. ).